Add proto validation for entity type in ProvidersService

[rdimitrov]

Summary

Ref https://github.com/stacklok/minder-stories/issues/94

Change Type

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• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

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Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 54.763%. remained the same
when pulling c3c2595 on validate-providers
into 3c86de3 on main.

[evankanderson]

It looks like these string enum values are capitalized?

[rdimitrov]

@evankanderson - Where is that, because I based it on these mappings here -

// Entity types as string-like enums. Used in CLI and other user-facing code
const (
	// RepositoryEntity is a repository entity
	RepositoryEntity EntityType = "repository"
	// BuildEnvironmentEntity is a build environment entity
	BuildEnvironmentEntity EntityType = "build_environment"
	// ArtifactEntity is an artifact entity
	ArtifactEntity EntityType = "artifact"
	// PullRequestEntity is a pull request entity
	PullRequestEntity EntityType = "pull_request"
	// ReleaseEntity is an entity abstracting a release
	ReleaseEntity EntityType = "release"
	// PipelineRunEntity is an entity abstracting a pipeline run (eg a workflow)
	PipelineRunEntity EntityType = "pipeline_run"
	// TaskRunEntity is an entity abstracting a task run (eg a step)
	TaskRunEntity EntityType = "task_run"
	// BuildEntity is an entity that represents a software build
	BuildEntity EntityType = "build"
	// UnknownEntity is an explicitly unknown entity
	UnknownEntity EntityType = "unknown"
)

[evankanderson]

Oops, I mis-read this line and the generated entity constants:

https://github.com/mindersec/minder/blob/http-send/internal/controlplane/handlers_entities.go#L45

It does look like we force these to lower-case on the server side before comparison, but I think this probably fine to start with.

[evankanderson]

Oops, I mis-read this line and the generated entity constants:

https://github.com/mindersec/minder/blob/http-send/internal/controlplane/handlers_entities.go#L45

It does look like we force these to lower-case on the server side before comparison, but I think this probably fine to start with.