RootCanal: Use the Supported Commands mask as source of truth

DualModeController now distinguishes between
- supported commands: commands enabled in the supported commands mask
- implemented commands: commands for which an implementation is provided

Command are handled following this logic:
- implemented and supported command: registered handler invoked
- supported but not implemented command: raise an assert
- unsupported commands: send command complete which ERR_UNKNOWN_COMMAND

Test: m root-canal
Bug: 266087760
Change-Id: Ie930d368bd5c20d67fbc3a5f49f68763e12bfb50