chore: Remove preproduction Avocado

[nschonni]

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[AutorestCI]

Automation for azure-sdk-for-python

Unable to detect any generation context from this PR.

[AutorestCI]

Automation for azure-sdk-for-go

Unable to detect any generation context from this PR.

[openapi-sdkautomation]

In Testing, Please Ignore

[Logs] (Generated from 65ce515, Iteration 1)

No readme.md specification configuration files were found that are associated with the files modified in this pull request.

[azuresdkci]

Can one of the admins verify this patch?

[erich-wang]

@nschonni , could you explain why should we remove avocado from pipeline?

@yungezz for awareness.

[nschonni]

package.json was bumped to 0.5.1 in #6887 so the prerelease is just running the same version of Avocado as the regular non-prerelease build

[nschonni]

Closing this one, because the pre-release will probably get bumped to 0.6.0 since Azure/avocado#48 landed
Edit: bump is in #7002