chore: replace deprecated substr() with substring()

[trivikr]

Which problem is this PR solving?

• The String.prototype.substr() is deprecated.

Short description of the changes

• This PR replaces String.prototype.substr() with String.prototype.substring()
• Similar change for aws packages was done in chore(aws): replace deprecated substr with substring #2551

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.75%. Comparing base (e7cc441) to head (07581dc).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2553   +/-   ##
=======================================
  Coverage   90.75%   90.75%           
=======================================
  Files         169      169           
  Lines        8018     8018           
  Branches     1632     1632           
=======================================
  Hits         7277     7277           
  Misses        741      741           

Files with missing lines	Coverage Δ
...y-instrumentation-cassandra/src/instrumentation.ts	81.65% <100.00%> (ø)
...try-instrumentation-fastify/src/instrumentation.ts	95.31% <100.00%> (ø)
...de/opentelemetry-instrumentation-knex/src/utils.ts	90.24% <100.00%> (ø)
...metry-propagator-ot-trace/src/OTTracePropagator.ts	95.91% <100.00%> (ø)

[github-actions]

This package does not have an assigned component owner and is considered unmaintained. As such this package is in feature-freeze and this PR will be closed with 14 days unless a new owner or a sponsor (a member of @open-telemetry/javascript-approvers) for the feature is found. It is the responsibility of the author to find a sponsor for this feature.
Are you familiar with this package? Consider becoming a component owner.

[trentm]

I'll sponsor to avoid the "unmaintained" pkg flows.

[trentm]

Thanks.