fix: Use margin instead of padding for the Snaps UI Container

[FrederikBolding]

Description

Use margin instead of padding for the Snaps UI Container. This fixes an issue where using certain components (such as Section) at the root would look weird.

Screenshots/Recordings

Before

After

[FrederikBolding]

This class was not actually in use.

[metamaskbot]

Builds ready [8e79f25]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

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

Page Load Metrics (1699 ± 98 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1398	2265	1700	207	99
		domContentLoaded	1389	2255	1673	211	101
		load	1450	2265	1699	205	98
		domInteractive	23	83	34	15	7
		backgroundConnect	9	77	28	22	11
		firstReactRender	18	90	42	25	12
		getState	5	65	17	19	9
		initialActions	0	1	0	0	0
		loadScripts	992	1843	1259	186	89
		setupStore	6	56	13	13	6
		uiStartup	1642	2541	1967	234	113

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: 0 Bytes (0.00%)
• common: 0 Bytes (0.00%)