config: Update CONNECT-UDP forwarding proxy config

[jeongseokson]

Commit Message: I removed the unnecessary certificates provided in the client context and added SNI field that matches the testing certificate in the repo. Additional Description: Risk Level: Low, this PR changes an example config. Testing: N/A Docs Changes: N/A Release Notes: N/A

[jeongseokson]

/assign @danzh2010

Hi Dan, can you review this PR related to #33775? Thank you.

[jmarantz]

/wait

[jeongseokson]

Thanks for reviewing, Dan. Do you have a write access to merge this @danzh2010? Should I ask someone else?

[danzh2010]

/assign @RyanTheOptimist

[rishabh78]

I am still seeing error stream reset: reset reason: protocol error, response details: http3.invalid_header_field

[danzh2010]

I am still seeing error stream reset: reset reason: protocol error, response details: http3.invalid_header_field

It doesn't look like the same problem though, please file a different issue and cc @DavidSchinazi