feat: allow updating initial_fetch_timeout in bootstrap

[andreik-n2]

What type of PR is this?

fix: ignore initial_fetch_timeout in bootstrap validation to allow modifying this parameter. Set initial_fetch_timeout to 0s by default.

What this PR does / why we need it: This PR updates the bootstrap validation logic to ignore the initial_fetch_timeout field within cds_config and lds_config during comparison. Also this PR sets default initial_fetch_timeout to 0s in the bootstrap config.

Which issue(s) this PR fixes:

Fixes #5574
Release Notes: Yes

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[zirain]

please add a release notes.

[zirain]

@andreik-n2 please fix the conflict.

[arkodg]

@andreik-n2 can we default to 0 ?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.71%. Comparing base (ced5d75) to head (7d4ba20).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7962      +/-   ##
==========================================
+ Coverage   73.69%   73.71%   +0.02%     
==========================================
  Files         237      237              
  Lines       35653    35654       +1     
==========================================
+ Hits        26274    26282       +8     
+ Misses       7520     7515       -5     
+ Partials     1859     1857       -2     

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[zirain]

@andreik-n2 can we default to 0 ?

I don't think this PR change the default value from 15s to 0s, it make it patched.
do you want to introduce a change?

[andreik-n2]

@andreik-n2 can we default to 0 ?

Hi @arkodg , are you sure you want set default to 0? I read that it could lead to having envoy proxy in not ready state indefinitely. Is it something you considered?

[arkodg]

@andreik-n2 can we default to 0 ?

Hi @arkodg , are you sure you want set default to 0? I read that it could lead to having envoy proxy in not ready state indefinitely. Is it something you considered?

yeah its better to fail hard for this case that configure partial config

[arkodg]

ptal @envoyproxy/gateway-maintainers

[arkodg]

LGTM thanks