Remove retry_policy and make timeout longer

[Warashi]

What this PR does / why we need it:

Make ext-authz-filter timeout longer, and remove retry_policy.

I realized that the Authz RPC is sometimes slow in the dev environment. So, I made the timeout longer.
After I checked the envoy log, the retry did not occur when the request was timeouted. So, I removed the retry_policy.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[ffjlabo]

LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 22.81%. Comparing base (032e430) to head (19a429e).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5203      +/-   ##
==========================================
- Coverage   22.82%   22.81%   -0.02%     
==========================================
  Files         420      420              
  Lines       45302    45302              
==========================================
- Hits        10340    10335       -5     
- Misses      34166    34172       +6     
+ Partials      796      795       -1     

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[khanhtc1202]

👍