[Secticide]

Description

Issue tracker: UUM-40635

Fixed an issue causing an editor style to not be found when initialising the Edit Control Scheme menu. This PR switches from referencing the editor style via string to referencing EditorStyles.toolbarSearchField directly. This editor style is present on all versions of Unity we support and prevents us from having to go down the route of specifying which version uses which spelling.

Changes made

AdvancedDropdownGUI.Styles.toolbarSearchField now references EditorStyles.toolbarSearchField directly rather than relying on a string search.

Checklist

Before review:

• Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • FogBugz ticket attached, example ([case %number%](https://issuetracker.unity3d.com/issues/...)).
  • FogBugz is marked as "Resolved" with next release version correctly set.
• Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

[ritamerkl]

LGTM, please wait for testing (@Pauliusd01)

[Pauliusd01]

LGTM. Checked with latest trunk Editor and one version that didn't have the style name change, both work correctly:

Latest trunk (has updated style name) -> Worked before this change -> still works with this change
2021.3.27f1 (does not have updated style name) -> Did not work before this change -> now works with this change