fix: set readOnlyRootFilesystem to true for redis and ha-proxy (#13315)

[jemag]

Fixes #13315

This PR sets readOnlyRootFilesystem to true for redis and ha-proxy thus improving the default security configuration in line with other workloads.

There does not seem to be any impact to those containers, although I would love for others to test it as well.

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[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (0e154b0) 49.01% compared to head (461d7fd) 49.01%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #13316   +/-   ##
=======================================
  Coverage   49.01%   49.01%           
=======================================
  Files         247      247           
  Lines       42685    42685           
=======================================
+ Hits        20921    20924    +3     
+ Misses      19647    19645    -2     
+ Partials     2117     2116    -1     

see 2 files with indirect coverage changes

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[crenshaw-dev]

Local test with kind checks out. If there are issues, we'll catch them in RCs. :-) Thanks @jemag!