feat(ui): add Mosaic Avatar component #31511

Job	Run time
Check Permissions	29s
Formatting \| Dedupe \| Changeset	59s
Build Packages	49s
Bundle size	1s
Publish with pkg-pr-new	1s
Integration Tests (${{ matrix.test-name }}, ${{ matrix.test-project }}${{ ((matrix.next-version && format(', {0}', matrix.next-version)) \|\| '') }})	1s
Unit Tests (${{ matrix.filter-label }})	1s
Static analysis	1s
	2m 22s

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