[Webcompat report dialog] Hidden "Send" button if reported URL is too long

[vadimstruts]

Resolves brave/brave-browser#42902

Added:

• ability to enable scroll bar in case of browser window height less then webcompat dialog height
• shortener for URL displayed on the dialog

Video:

2024-12-18.21-12-23.mp4

Additional Notes:

• Webcompat Reporter modal dialog content does not receive resize events, so window.onresize doesn't work.
• overflow-y doesn't work too (on the #root or on the body).

I had to add observing of the OnWidgetBoundsChanged with help of views::WidgetObserver to handle Webcompat Reporter modal dialog resize and show the scrollbar instead of just hiding part of dialog's content, without any possibility to interact with hidden part.
When dialog's content initializes, we send init request to backend to start one iteration of the OnWidgetBoundsChanged and get actual height, to correctly handle the situation, when screen is to small and modal dialog height is greater then screen's. Then if user changes the height of the browser, the OnWidgetBoundsChanged sends correct height to the dialog's content.

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally:
  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
  • npm run presubmit wiki, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[brave-builds]

A Storybook has been deployed to preview UI for the latest push