Fix tool step type in vMCP CRD

[JAORMX]

The actual type is type: "tool" not tool_call.

pkg/vmcp/composer/composer.go:	// StepTypeTool executes a backend tool.
pkg/vmcp/composer/composer.go:	StepTypeTool StepType = "tool"

So this fixes this erroneous reference.

Signed-off-by: Juan Antonio Osorio ozz@stacklok.com

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.84%. Comparing base (8ce0337) to head (38d5f70).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...lpha1/virtualmcpcompositetooldefinition_webhook.go	50.00%	1 Missing ⚠️
...-operator/api/v1alpha1/virtualmcpserver_webhook.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2608   +/-   ##
=======================================
  Coverage   55.84%   55.84%           
=======================================
  Files         312      312           
  Lines       29541    29541           
=======================================
+ Hits        16496    16498    +2     
+ Misses      11603    11601    -2     
  Partials     1442     1442           

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