Create new build event ID type for external repositories

### Description of the feature request:

https://github.com/bazelbuild/bazel/blob/1f4aa9e65a5086a59ced0ecb1a6123c5bc772dda/src/main/java/com/google/devtools/build/lib/repository/RepositoryFailedEvent.java#L48-L59

The current event id is a label looks like `label: "//external:+_repo_rules+remote"`, we should avoid using `EXTERNAL_PACKAGE_IDENTIFIER` anymore.

### Which category does this issue belong to?

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### What underlying problem are you trying to solve with this feature?

_No response_

### Which operating system are you running Bazel on?

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### What is the output of `bazel info release`?

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### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

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### What's the output of `git remote get-url origin; git rev-parse HEAD` ?

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### Have you found anything relevant by searching the web?

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### Any other information, logs, or outputs that you want to share?

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Start with src/main/java/com/google/devtools/build/lib/repository/RepositoryFailedEvent.java at lines 48-59, then trace uses of EXTERNAL_PACKAGE_IDENTIFIER and the current event ID. Define the required replacement event ID type for external repositories and verify that this event no longer uses the existing external package identifier.

Written by the indexing model from the issue text.