Add tests for the new pipelines builder

[bogdandrutu]

Depends on #5542

[bogdandrutu]

/cc @mx-psi this is the 5th PR extracted from #5512

[codecov]

Codecov Report

Merging #5544 (a354a07) into main (c099f6a) will increase coverage by 0.19%.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##             main    #5544      +/-   ##
==========================================
+ Coverage   90.80%   90.99%   +0.19%     
==========================================
  Files         194      194              
  Lines       11485    11485              
==========================================
+ Hits        10429    10451      +22     
+ Misses        833      818      -15     
+ Partials      223      216       -7     

Impacted Files	Coverage Δ
service/internal/builder/pipelines_builder.go	91.27% <75.00%> (+3.48%)	⬆️
service/internal/builder/receivers_builder.go	83.85% <83.33%> (+1.86%)	⬆️
pdata/internal/common.go	91.85% <0.00%> (-0.75%)	⬇️
service/internal/builder/exporters_builder.go	96.11% <0.00%> (+5.82%)	⬆️
service/internal/pipelines/pipelines.go	82.10% <0.00%> (+9.47%)	⬆️
internal/testcomponents/example_processor.go	100.00% <0.00%> (+11.11%)	⬆️

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[mx-psi]

What's the issue here?

[bogdandrutu]

The problem is that we build the receivers by looking at configs, and if used in one pipeline we create/initialize it. With this logic if there is a receiver in a pipeline without a config we don't create/initialize it, but this is not a "Valid" config and fails config.Validate().