Fix Oxide scanner bugs

[philipp-spiess]

Fixes #15632
Fixes #15740

This PR fixes a number of Oxide scanner bugs reported over various channels, specifically:

• When using the Svelte class shorthand split over various lines, we weren't extracting class names properly:

  <div
    class:underline={isUnderline}>
  </div>

• We now extract classes when using the class shortcut in Angular:

  <div [class.underline]=\"bool\"></div>

• We now validate parentheses within arbitrary candidates so that we don't consume invalid arbitrary candidates anymore which allows us to parse the following case properly:

  const classes = [wrapper("bg-red-500")]

Test plan

Added unit tests