[componenttest] Remove GetFactory from nopHost

[evan-bradley]

Description

The GetFactory method was moved from component.Host to hostcapabilities.ComponentFactory. From what I can tell, this method is not used on the no-op host anywhere in core, and introduces an implicit loop in the dependency graph, so we should remove it before componenttest is made stable.

Link to tracking issue

Works toward #13490

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.24%. Comparing base (1c8a5c4) to head (f0f2f88).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13577      +/-   ##
==========================================
- Coverage   92.24%   92.24%   -0.01%     
==========================================
  Files         614      614              
  Lines       33686    33684       -2     
==========================================
- Hits        31075    31071       -4     
- Misses       2076     2077       +1     
- Partials      535      536       +1     

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[songy23]

Looks like contrib needs fixing after this PR https://github.com/open-telemetry/opentelemetry-collector/actions/runs/16781207495/job/47520490032?pr=13577

[evan-bradley]

I've been looking into that, unfortunately it's more complicated than just fixing up a test: it's a generated test, so either we have to disable lifecycle tests on the receivercreator, create a servicetest package that mdatagen uses that offers a service with all hostcapabilities interfaces implemented (or some combination of them), or some third option.

Right now I'm leaning toward disabling the generated tests and writing more comprehensive tests to validate the receiver's startup behavior. The receiver is unique enough that I think it warrants having its own tests.

[bogdandrutu]

@evan-bradley I think we should change mdatagen to call with a host that implements the hostcapabilities.ComponentFactory as well. What do you think about doing that first?

[evan-bradley]

@bogdandrutu that's okay with me. I've implemented it here: #13589.

I think that unless we provide options to generate a test matrix for whether calls to Start are successful for a given host and the interfaces it implements, it will come down to the component to write its own lifecycle tests for its own behavior. For example, components that want hostcapabilities.ComponentFactory should probably error out if the host doesn't implement that interface, but some components that use hostcapabilities.ModuleInfo will simply emit a log.