[Bug report] Lance Spark 0.5.1 reports Namespace not found instead of NoSuchSchemaException

### Version

main branch

### Describe what's wrong

`LanceSparkRESTServiceIT.testCreateTableInNonExistentSchemaFails` passes on lance-spark-bundle 0.2.0 and 0.4.0, and fails on 0.5.1.

Creating a table in a missing schema still fails, but 0.5.1 surfaces `Namespace not found: Schema ... does not exist` instead of a message that contains `NoSuchSchemaException`. The test requires all of `NoSuchSchemaException`, the schema name, and `does not exist`.

### Error message and/or stacktrace

```text
LanceSparkRESTServiceIT > testCreateTableInNonExistentSchemaFails() FAILED
org.opentest4j.AssertionFailedError: Expected error message to contain "NoSuchSchemaException",
but message was: Namespace not found: Schema LanceRESTService_metalake_....spark_missing_ns_... does not exist
at org.apache.gravitino.lance.integration.test.LanceSparkRESTServiceIT.testCreateTableInNonExistentSchemaFails(LanceSparkRESTServiceIT.java:302)
```

Gradle task: `:lance:lance-rest-server:testLanceSparkBundle_0_5_1`

### How to reproduce

1. Use current `main`.
2. Run:

```bash
./gradlew :lance:lance-rest-server:lanceSparkMatrixTest \
-PlanceSparkBundleVersions=0.5.1 \
-PskipDockerTests=true \
-PskipWeb=true
```

Or run the Lance compatibility matrix workflow (default versions include `0.2.0,0.4.0,0.5.1`).

Example run: https://github.com/danhuawang/gravitino/actions/runs/34376085905/job/102549165090

### Additional context

The failure is an error-message / client-bundle compatibility issue, not a CI workflow problem. The test can accept both `NoSuchSchemaException` and `Namespace not found`, or the 0.5.1 path can preserve the original exception type in the Spark error text.

Start with LanceSparkRESTServiceIT.testCreateTableInNonExistentSchemaFails and run :lance:lance-rest-server:lanceSparkMatrixTest with lanceSparkBundleVersions=0.5.1, skipDockerTests=true, and skipWeb=true. Compare the 0.2.0, 0.4.0, and 0.5.1 results; done means the failure still includes the schema name and does not exist while handling the expected exception wording consistently.

Written by the indexing model from the issue text.