[8.6.0] Cannot fetch a file without a checksum in ENFORCE mode

### Description of the bug:

```
FATAL: bazel crashed due to an internal error. Printing stack trace:
java.lang.RuntimeException: Unrecoverable error while evaluating node 'Key[moduleName=rules_pkg, registryUrl=https://bcr.bazel.build/]' (requested by nodes 'com.google.devtools.build.lib.bazel.bzlmod.BazelModuleResolutionValue$$Lambda/0x00000000a6688000@36e0bd2f')
at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:547)
at com.google.devtools.build.lib.concurrent.AbstractQueueVisitor$WrappedRunnable.run(AbstractQueueVisitor.java:435)
at java.base/java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: java.lang.IllegalStateException: Cannot fetch a file without a checksum in ENFORCE mode. This is a bug in Bazel, please report at https://github.com/bazelbuild/bazel/issues/new/choose.
at com.google.common.base.Preconditions.checkState(Preconditions.java:513)
at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.doGrabFile(IndexRegistry.java:204)
at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.grabFile(IndexRegistry.java:154)
at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.grabJsonFile(IndexRegistry.java:309)
at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.grabJson(IndexRegistry.java:326)
at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.getYankedVersions(IndexRegistry.java:559)
at com.google.devtools.build.lib.bazel.bzlmod.YankedVersionsFunction.compute(YankedVersionsFunction.java:51)
at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:467)
... 6 more
```

### Which category does this issue belong to?

External Dependency

### What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

_No response_

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

macOS

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

release 8.6.0

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

_No response_

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

```text

```

### If this is a regression, please try to identify the Bazel commit where the bug was introduced with bazelisk --bisect.

_No response_

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

_No response_

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

_No response_