Update git submodules

* Update frameworks/support from branch 'androidx-main'
  to 9d21dc85e9be2a7827b67cd2e7a1da148d353de3
  - Merge "[GH] Enable signature verification for playground" into androidx-main
  - [GH] Enable signature verification for playground
    
    ## Proposed Changes
    
    Enable Gradle signature verification for playground projects
    
    ## Testing
    
    Test: in room/ ./gradlew tasks
    
    This is an imported pull request from https://github.com/androidx/androidx/pull/335.
    
    Resolves #335
    Github-Pr-Head-Sha: 82a6fd3d8e7bb32f9568e0afc28a3e0581161f8e
    GitOrigin-RevId: 3844fd5a524b2218620f7dee91ff5df5328f0480
    Change-Id: I61551b3debb883c7b81435d84d8fb448200f6f39