fix(proxy-agent): add fallback value for servername when using reques…

[Viiprogrammer]

This relates to...

#3988

Changes

Added fallback for requestTls.servername

Bug Fixes

Fix servername when using requestTls #3988

Status

• [x] I have read and agreed to the Developer's Certificate of Origin
• [x] Tested
• [ ] Benchmarked (optional)
• [ ] Documented
• [x] Review ready
• [ ] In review
• [ ] Merge ready

[Viiprogrammer]

Can you add a test for it?

Need to be covered by tests like here ?

Yes, I'll add tests if needed

[metcoder95]

Can you add a test for it?

Need to be covered by tests like here ?

Yes, I'll add tests if needed

sure, that works 👍