fix(deployment): use Config instead of ConfigBackoff when fetching deploy config

[ecrupper]

users supplying a bad ref should not result in a several second response time. the backoff is only helpful when dealing with concurrent webhooks with legit refs

[KellyMerrick]

lgtm

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 56.56%. Comparing base (7d74bfc) to head (4611894).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
api/deployment/get_config.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1239   +/-   ##
=======================================
  Coverage   56.56%   56.56%           
=======================================
  Files         629      629           
  Lines       35609    35609           
=======================================
  Hits        20144    20144           
  Misses      14784    14784           
  Partials      681      681           

Files with missing lines	Coverage Δ
api/deployment/get_config.go	0.00% <0.00%> (ø)