Use standalone crddiff tool

[turkenf]

Description of your changes

This PR uses the standalone crddiff tool.

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Tested with the uptest in the below comments.

[turkenf]

/test-examples="examples/conditionalaccess/v1beta2/accesspolicy.yaml"

[turkenf]

/test-examples="examples/applications/v1beta1/application.yaml"

[turkenf]

/test-examples="examples/conditionalaccess/v1beta2/accesspolicy.yaml"

[turkenf]

/test-examples="examples/applications/v1beta1/application.yaml"

[turkenf]

/test-examples="examples/conditionalaccess/v1beta2/accesspolicy.yaml"

https://github.com/crossplane-contrib/provider-upjet-azuread/actions/runs/11616369681

[turkenf]

/test-examples="examples/applications/v1beta1/application.yaml"

https://github.com/crossplane-contrib/provider-upjet-azuread/actions/runs/11616370685

[mergenci]

Thanks @turkenf 🙌 LGTM. For posterity, crddiff used to be a command-line argument to uptest. crddiff didn't fit uptest's purpose in the first place, so it was removed before donating uptest to the community. Now that we have updated the build module to use crossplane/build, which doesn't have crddiff, we are running it from upbound/uptest.