ui/profile/icicle: Always group by function name

[metalmatze]

• ui/profile/IcicleGraph: Fix GroupBy dropdown background color
• ui/profile/IcicleGraph: Always group by function name

[alwaysmeticulous]

🤖 Meticulous spotted visual differences in 81 of 318 screens tested: view and approve differences detected.

_{Last updated for commit 46a678e. This comment will update as new commits are pushed.}