docs: updates README.md for @opentelemetry/propagator-b3

[OmkarKirpan]

Which problem is this PR solving?

• fixes code samples provided in README.md for OpenTelemetry Propagator B3 package

Short description of the changes

• added proper required packges in code samples

[codecov]

Codecov Report

Merging #2342 (45421b4) into main (b67ca05) will increase coverage by 0.13%.
The diff coverage is n/a.

❗ Current head 45421b4 differs from pull request most recent head 56bb707. Consider uploading reports for the commit 56bb707 to get more accurate results

@@            Coverage Diff             @@
##             main    #2342      +/-   ##
==========================================
+ Coverage   92.34%   92.47%   +0.13%     
==========================================
  Files         128      122       -6     
  Lines        4244     4132     -112     
  Branches      867      859       -8     
==========================================
- Hits         3919     3821      -98     
+ Misses        325      311      -14     

Impacted Files	Coverage Δ
...opentelemetry-api-metrics/src/NoopMeterProvider.ts
...ages/opentelemetry-api-metrics/src/types/Metric.ts
...kages/opentelemetry-api-metrics/src/api/metrics.ts
.../opentelemetry-api-metrics/src/api/global-utils.ts
...emetry-api-metrics/src/platform/node/globalThis.ts
...ackages/opentelemetry-api-metrics/src/NoopMeter.ts