fix: Allow gRPC connections from gRPC versions >1.17.x

[jannfis]

gRPC has changed handshake processing from v1.17 upwards, in a way that's incompatible with default cmux processing (see grpc/grpc-go#2406 and https://github.com/soheilhy/cmux#limitations).

This fix lets gRPC clients >1.17 do a handshake with Argo CD gRPC server.

Fixes #6525

Signed-off-by: jannfis jann@mistrust.net

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[codecov]

Codecov Report

Merging #6577 (173b63a) into master (f74d807) will decrease coverage by 0.01%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master    #6577      +/-   ##
==========================================
- Coverage   41.26%   41.25%   -0.02%     
==========================================
  Files         156      156              
  Lines       20673    20675       +2     
==========================================
- Hits         8531     8529       -2     
- Misses      10935    10938       +3     
- Partials     1207     1208       +1     

Impacted Files	Coverage Δ
server/server.go	54.95% <50.00%> (ø)
server/rbacpolicy/rbacpolicy.go	79.03% <0.00%> (-4.31%)	⬇️
server/application/logs.go	84.48% <0.00%> (-1.24%)	⬇️

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[jessesuen]

Great catch!