Cherry pick #6766 and #6952 to v1.62.x release branch

[arvindbr8]

Cherry-pick #6766 and #6952

RELEASE NOTES:

• rpc_util: The RecvBufferPool option is now active during unary RPC and in compression is enabled.
• stats: The stats handler now accurately tracks uncompressedBytes during unary RPC calls.

[codecov]

Codecov Report

Merging #7019 (5948513) into v1.62.x (9d981b0) will increase coverage by 0.03%.
The diff coverage is 94.44%.

Additional details and impacted files

@@             Coverage Diff             @@
##           v1.62.x    #7019      +/-   ##
===========================================
+ Coverage    82.27%   82.31%   +0.03%     
===========================================
  Files          296      296              
  Lines        31449    31461      +12     
===========================================
+ Hits         25876    25897      +21     
+ Misses        4510     4494      -16     
- Partials      1063     1070       +7     

Files	Coverage Δ
internal/transport/transport.go	94.07% <100.00%> (+1.30%)	⬆️
server.go	81.53% <100.00%> (+0.50%)	⬆️
rpc_util.go	77.77% <91.66%> (+0.37%)	⬆️

... and 20 files with indirect coverage changes