fix(sdk-node): ensure invalid metric reader config does not throw on startup

[pichlermarc]

Which problem is this PR solving?

Our approach to environment vars is that they should not throw if set incorrectly, but instead gracefully handle it and fall back to defaults. This is backed by the specification:

For sources accepting a numeric value, if the user provides a value which is outside the valid range for the configuration item, the implementation SHOULD generate a warning and gracefully ignore the setting, i.e., treat them as not set. In particular, implementations SHOULD NOT assign a custom interpretation e.g. to negative values if a negative value does not naturally apply to a configuration and does not have an explicitly specified meaning, but treat it like any other invalid value.

This PR aligns the NodeSDK setup of the PeriodicExportingMetricReader accordingly:

• treats values that are negative as unset and warns
• treats values that are interdependent (timeout and interval) by clamping these as needed

Not doing this currently causes the PeriodicExportingMetricReader to throw on startup ([1], [2], [3]) and crash the app, which can happen particularly often when just reducing OTEL_METRIC_EXPORT_INTERVAL below 30_000 (30s).

Fixes #5550 (see specifically #5550 (comment))

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Added unit tests

[codecov]

Codecov Report

❌ Patch coverage is 97.95918% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.39%. Comparing base (77040f3) to head (f8736b5).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ental/packages/opentelemetry-sdk-node/src/utils.ts	97.91%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6295   +/-   ##
=======================================
  Coverage   95.39%   95.39%           
=======================================
  Files         316      316           
  Lines        9548     9574   +26     
  Branches     2210     2216    +6     
=======================================
+ Hits         9108     9133   +25     
- Misses        440      441    +1     

Files with missing lines	Coverage Δ
...imental/packages/opentelemetry-sdk-node/src/sdk.ts	95.85% <100.00%> (-0.50%)	⬇️
...ental/packages/opentelemetry-sdk-node/src/utils.ts	94.78% <97.91%> (+0.92%)	⬆️

... and 1 file with indirect coverage changes

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