fix: decrease level of unsupported-version logs to warn

[naseemkullah]

Which problem is this PR solving?

• There are situations when using a non instrumentable version of a module are unavoidable for the moment. The behaviour to skip instrumentation is correct, though merits a warning as this generally means that the non-instrumented module is due for an update.

Short description of the changes

• Reduces the log level from error to warn when skipping non supported versions of modules.

[codecov]

Codecov Report

Merging #1532 into master will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master    #1532   +/-   ##
=======================================
  Coverage   93.82%   93.82%           
=======================================
  Files         154      154           
  Lines        4762     4762           
  Branches      951      951           
=======================================
  Hits         4468     4468           
  Misses        294      294           

Impacted Files	Coverage Δ
...telemetry-node/src/instrumentation/PluginLoader.ts	93.82% <0.00%> (ø)

[dyladan]

Please update the PR name to something that will make more sense in the automated changelog