[Bug report] preloadOwner is not best-effort: an uninitialized GravitinoEnv fails the whole list request

### Version

main branch

### Describe what's wrong

`MetadataAuthzHelper.preloadOwner` is a best-effort cache warm-up - its `catch (Exception e)` logs and ignores any failure. But the entity-store lookup sits *outside* that `try`:

```java
private static void preloadOwner(Entity.EntityType entityType, NameIdentifier[] nameIdentifiers) {
if (!GravitinoEnv.getInstance().cacheEnabled()) {
return;
}
EntityStore entityStore = GravitinoEnv.getInstance().entityStore(); // <-- outside the try
try {
entityStore.relationOperations().batchListEntitiesByRelation(...);
} catch (Exception e) {
LOG.warn("Ignore preloadOwner error:{}", e.getMessage(), e);
}
}
```

`GravitinoEnv.entityStore()` has `Preconditions.checkArgument(initialized, "GravitinoEnv is not initialized.")`, so when the environment is not initialized that `IllegalArgumentException` escapes the warm-up, propagates out of `MetadataAuthzHelper.filterByExpression`, and fails the entire list request with HTTP 400 - even though nothing about the requested listing actually failed.

### Error message and/or stacktrace

```
{"code":1001,"type":"IllegalArgumentException",
"message":"Failed to operate tag(s) operation [LIST] under object [object1.object2], reason [GravitinoEnv is not initialized.]"}

java.lang.IllegalArgumentException: GravitinoEnv is not initialized.
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:143)
at org.apache.gravitino.GravitinoEnv.entityStore(GravitinoEnv.java:261)
at org.apache.gravitino.server.authorization.MetadataAuthzHelper.preloadOwner(MetadataAuthzHelper.java:552)
at org.apache.gravitino.server.authorization.MetadataAuthzHelper.filterByExpression(MetadataAuthzHelper.java:364)
at org.apache.gravitino.server.web.rest.MetadataObjectTagOperations.lambda$listTagsForMetadataObject$9(MetadataObjectTagOperations.java:217)
```

### How to reproduce

Version: main branch. Any list endpoint that routes through `MetadataAuthzHelper.filterByExpression` while `GravitinoEnv` is uninitialized returns 400. Observable on `main` with:

```bash
./gradlew :server:test -PskipITs --tests "org.apache.gravitino.server.web.rest.TestMetadataObjectTagOperations"
```

Three tests fail with 400 instead of 200: `testListTagsForObject`, `testListTagsForObjectUnderHierarchicalSchema`, `testListTagsDeduplicatesDifferentAssignmentValues`.

A booted server initializes `GravitinoEnv`, so production traffic does not hit this today - the defect is that a helper documented and coded as ignorable can still abort the request.

### Additional context

Found while adding tag support for Semantic Models (#12615). The fix is to move the lookup inside the existing `try`.

Start in server authorization MetadataAuthzHelper.preloadOwner around line 552, then run the named TestMetadataObjectTagOperations tests with ./gradlew :server:test -PskipITs --tests "org.apache.gravitino.server.web.rest.TestMetadataObjectTagOperations". Done means an uninitialized GravitinoEnv no longer aborts list requests and testListTagsForObject, testListTagsForObjectUnderHierarchicalSchema, and testListTagsDeduplicatesDifferentAssignmentValues return 200.

Written by the indexing model from the issue text.