[chore] Improve startup error message

[TylerHelmuth]

Description:
Update's the collector's execute command to return a more usable error message when no configuration is provided.

Link to tracking Issue:
Fixes #5648

Testing:
Scenario already covered in existing unit test.

[codecov]

Codecov Report

Merging #5978 (51069ca) into main (940943c) will decrease coverage by 0.10%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main    #5978      +/-   ##
==========================================
- Coverage   92.24%   92.14%   -0.11%     
==========================================
  Files         212      212              
  Lines       13263    13269       +6     
==========================================
- Hits        12235    12227       -8     
- Misses        811      824      +13     
- Partials      217      218       +1     

Impacted Files	Coverage Δ
service/command.go	54.54% <83.33%> (-24.03%)	⬇️
service/flags.go	80.76% <0.00%> (-7.70%)	⬇️
service/config_provider.go	76.92% <0.00%> (-7.70%)	⬇️
...er/loggingexporter/internal/otlptext/databuffer.go	99.12% <0.00%> (+<0.01%)	⬆️

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