refac: migrate ExamplesLink and EmphasizedNode components from enzyme to RTL

[EshaanAgg]

Which problem is this PR solving?

Fixes part of #1668

Description of the changes

• Migrates ExamplesLink and EmphasizedNode components from enzyme to RTL
• Replaces snapshot testing with actual test for the URLs

How was this change tested?

Running the tests locally

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3cc0e88) 96.54% compared to head (834f0e6) 96.54%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2066   +/-   ##
=======================================
  Coverage   96.54%   96.54%           
=======================================
  Files         255      255           
  Lines        7622     7622           
  Branches     1985     1985           
=======================================
  Hits         7359     7359           
  Misses        263      263           

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[yurishkuro]

Thanks!