fix: Move foreground state properties from metamask slice to appState slice

[MajorLift]

Description

1. Moves properties in the metamask Redux slice that are not part of background (i.e. controller-derived) state into the appState slice.

The affected state properties are as follows:

  customNonceValue: string;
  isAccountMenuOpen: boolean;
  isNetworkMenuOpen: boolean;
  nextNonce: string | null;
  pendingTokens: {
    [address: string]: Token & { isCustom?: boolean; unlisted?: boolean };
  };
  welcomeScreenSeen: boolean;
  confirmationExchangeRates: ContractExchangeRates;

• Foreground properties that are a part of AppStateController state have not been moved into the appState slice, and will remain in the unflattened metamask slice.
  • It's not immediately clear why the properties listed above were excluded from AppStateController state, but since all of them appear to neither require persistence beyond a given session, nor anonymization of PII, I'm opting to maintain the status quo and keep them out of controller state.
• The isInitialized property is not included, because it's derived from background state before the Redux store is instantiated, and is updated by the PatchStore which supplies it directly to the metamask slice.

2. Groups appState slice selectors in ui/selectors/selectors.js together.

Related issues

• Closes [Unflattening #0] Remove non controller-state properties from metamask slice. #29601
• Contributes to https://github.com/MetaMask/MetaMask-planning/issues/2895
• 0 of 7 PRs that will close [EPIC] Unflatten metamask Redux slice #29600
• Blocking https://github.com/MetaMask/MetaMask-planning/issues/2894
  • refactor: Unflatten MetamaskController stores #28723
  • refactor: Unflatten metamask Redux slice and convert to TypeScript #28929
  • refactor: Unflatten tests #28776

Manual testing steps

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
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Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

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[metamaskbot]

Builds ready [859ae89]

• builds: chrome, firefox
• builds (flask): chrome, firefox
• builds (MMI): chrome
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • content-script: 0
  • offscreen: 0

Page Load Metrics (1768 ± 77 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1548	2325	1772	173	83
		domContentLoaded	1519	2227	1736	160	77
		load	1549	2239	1768	161	77
		domInteractive	22	70	35	12	6
		backgroundConnect	11	93	37	23	11
		firstReactRender	16	77	40	24	12
		getState	6	68	15	16	8
		initialActions	0	0	0	0	0
		loadScripts	1111	1743	1292	149	72
		setupStore	7	68	21	22	10
		uiStartup	1733	2604	2020	197	95

Bundle size diffs [🚀 Bundle size reduced!]

• background: 0 Bytes (0.00%)
• ui: -130 Bytes (-0.00%)
• common: -54 Bytes (-0.00%)

[metamaskbot]

Builds ready [835ffa3]

• builds: chrome, firefox
• builds (flask): chrome, firefox
• builds (MMI): chrome
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • content-script: 0
  • offscreen: 0

Page Load Metrics (1577 ± 44 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1488	1781	1580	77	37
		domContentLoaded	1436	1761	1550	86	42
		load	1475	1852	1577	91	44
		domInteractive	21	137	44	29	14
		backgroundConnect	8	65	24	19	9
		firstReactRender	15	101	49	36	17
		getState	4	78	20	22	10
		initialActions	0	1	0	0	0
		loadScripts	1030	1313	1151	76	36
		setupStore	6	52	9	10	5
		uiStartup	1642	2471	1921	236	113

Bundle size diffs [🚀 Bundle size reduced!]

• background: 0 Bytes (0.00%)
• ui: -130 Bytes (-0.00%)
• common: -54 Bytes (-0.00%)

[EtherWizard33]

re-approving on behalf of @NidhiKJha