feat(GlFilteredSearch): add props for adding additional HTML attributes

What does this MR do?

Closes #1688 (closed)

Adds searchButtonAttributes and searchInputAttributes props to GlFilteredSearch. These props allow you to add HTML attributes to the search button and the search input. This is helpful for QA E2E specs because then data-qa-selector attributes can be added to these elements.

The searchButtonAttributes prop is added to the search button

The searchInputAttributes prop is added in three places

1. The input when there are no tokens

2. The input when editing a token

3. The div that is clicked to add a new token

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• GitLab UI's contributing guidlines.
• [-] If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• [-] If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • GitLab: mr_url
  • CustomersDot: GlFilteredSearch and GlSearchBoxByClick not used.
  • Status Page: GlFilteredSearch and GlSearchBoxByClick not used.
• Added the ~"component:*" label(s) if applicable.