Fix templates to support testcases without an extension

[pyoor]

When attempting to publish a bug with a testcase that lacks an extension, the testcase basename is used instead.

[sentry]

Codecov Report

❌ Patch coverage is 95.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 63.31%. Comparing base (f45b5cb) to head (e554a05).

Files with missing lines	Patch %	Lines
server/frontend/src/helpers.js	95.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1142      +/-   ##
==========================================
+ Coverage   63.26%   63.31%   +0.05%     
==========================================
  Files         177      177              
  Lines       12124    12144      +20     
  Branches      541      879     +338     
==========================================
+ Hits         7670     7689      +19     
- Misses       4420     4421       +1     
  Partials       34       34              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.