[extension/opamp] Report Available Components in the OpAMP extension

[mrsillydog]

Important (read before submitting)

Is your feature request related to a problem? Please describe.

I would like to be able to access what components are accessible in the collector programmatically via the OpAMP extension. This would be especially useful for dynamically reacting to the available components depending on the build of the collector.

Describe the solution you'd like

I would like to use the module info which was made accessible to extensions in #10876 in tandem with the upcoming release of opamp-go, which should contain the implementation of the AvailableComponents message, to support retrieval of the available collector components.