Use Material Symbols outline icon variant

[AndyScherzinger]

Topic and Scope

With the upcoming Hub release we switch to outline icons, for cookbook the only applicable item is the delete icon

Concerns/issues

purely a delete icon replacement

Formal requirements

There are some formal requirements that should be satisfied. Please mark those by checking the corresponding box.

• I did check that the app can still be opened and does not throw any browser logs
• I created tests for newly added PHP code (check this if no PHP changes were made)
• I updated the OpenAPI specs and added an entry to the API changelog (check if API was not modified)
• I notified the matrix channel if I introduced an API change

[github-actions]

Test Results

   12 files      1 errors  579 suites   1m 29s ⏱️
  581 tests   580 ✅ 1 💤 0 ❌
2 312 runs  2 307 ✅ 5 💤 0 ❌

For more details on these parsing errors, see this check.

Results for commit 4e10f87.