Add Tip icon to library and use in the Tip component

[ndiego]

Description

This simple PR furthers the mission of ensuring all icons used in the Gutenberg UI are actually available in the icons library and are not hardcoded. One such icon is the Tip icon (lightbulb), which is used at the bottom of the inserter (see screenshot).

In this PR, the svg code for the icon is moved to the icons library and the Tip component is updated to reflect this change. This issue was originally mentioned here #35187 (comment) and I just now got to it 😅

Testing Instructions

1. Open the inserter and make sure the Tip icon looks the same as it did previously.

Screenshots

Types of changes

New feature

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).
• I've updated related schemas if appropriate.

[jasmussen]

Looks great, matches icon name in Figma, tests well:

Excellent cleanup, nice work!

[jasmussen]

Oh, I guess we should mention this in the changelog, my bad. @ndiego would you mind adding a small note?

https://github.com/WordPress/gutenberg/blob/trunk/packages/icons/CHANGELOG.md

[ndiego]

@jasmussen oh good catch. I have updated here #38450