WIP: Replace angle-down with chevron

What does this MR do?

Location	Before	After
Compare diff dropdown
Group tree
MR discussion
Log line expand	Need help finding rendered example	TBD
Web IDE	Need help finding rendered example	TBD
MR collapsible extension	Need help finding rendered example	TBD
Filtered search	Need help finding rendered example	TBD
Terms
Header nav help
Header nav profile
Header nav new
Header nav
Snippets	Need help finding rendered example	TBD
Geo nodes	Need help finding rendered example	TBD
Group analytics contribution
cell	cell	cell
cell	cell	cell
cell	cell	cell

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

N/A

Security

N/A