Fix format strings

[AndiDog]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Use static format string since err.Error() shouldn't be used as one as it could contain %.

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• cherry-pick candidate

Release note:

NONE

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 52.84%. Comparing base (f2226d1) to head (0b849eb).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
controllers/azuremanagedmachinepool_controller.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5743   +/-   ##
=======================================
  Coverage   52.84%   52.84%           
=======================================
  Files         278      278           
  Lines       29610    29610           
=======================================
  Hits        15647    15647           
  Misses      13146    13146           
  Partials      817      817           

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[mboersma]

/lgtm
/approve

Thanks for catching this @AndiDog!

FWIW, the new linter configuration with Go 1.24 will also catch this; I was forced to fix it in #5661.

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 3958c74f8e586f0ca6d7f73869b777f81d4eb7ec

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mboersma

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