fix: add secureConnectionStart to https only

[Abinet18]

Which problem is this PR solving?

Avoid adding secure connection start span event for insecure connection

Fixes # (issue)
#3848

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

How Has This Been Tested?

Tested through document load instrumentation and checking the resulting span events

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #3879 (e54597e) into main (dccd906) will decrease coverage by 0.24%.
The diff coverage is 100.00%.

❗ Current head e54597e differs from pull request most recent head 1026595. Consider uploading reports for the commit 1026595 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3879      +/-   ##
==========================================
- Coverage   93.13%   92.89%   -0.24%     
==========================================
  Files         298      297       -1     
  Lines        8868     8839      -29     
  Branches     1826     1817       -9     
==========================================
- Hits         8259     8211      -48     
- Misses        609      628      +19     

Impacted Files	Coverage Δ
packages/opentelemetry-sdk-trace-web/src/utils.ts	94.67% <100.00%> (+0.09%)	⬆️

... and 19 files with indirect coverage changes