fix(bigquery): prevent NullPointerException in OTel tracing when JobId is null (#13301)

b/517929704

This PR addresses a `NullPointerException` that occurs in the BigQuery
client library when OpenTelemetry tracing is enabled and operations are
performed on jobs that do not have a client-assigned `JobId` at the
start of the call.

A notable case where this happens is during dry-run queries (often used
to determine statement type or fetch statistics) where
`JobInfo.getJobId()` returns null. The OTel instrumentation was
attempting to extract attributes from the `JobId` without checking for
nullability.

**Changes:**
* Added null checks before calling `JobId.getOtelAttributes()` in
`BigQueryImpl.create(JobInfo)` (line 455).
* Added null checks before calling `JobId.getOtelAttributes()` in
`BigQueryImpl.getQueryResults(JobId)` (line 2128).
* These changes align with the safe-check pattern already implemented in
`BigQueryImpl.queryWithTimeout` (line 2075).

Author: keshavdandeva

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryImpl.java

@@ -452,7 +452,10 @@ && getOptions().getOpenTelemetryTracer() != null) {
           getOptions()
               .getOpenTelemetryTracer()
               .spanBuilder("com.google.cloud.bigquery.BigQuery.createJob")
-              .setAllAttributes(jobInfo.getJobId().getOtelAttributes())
+              .setAllAttributes(
+                  jobInfo.getJobId() != null
+                      ? jobInfo.getJobId().getOtelAttributes()
+                      : Attributes.empty())
               .setAllAttributes(otelAttributesFromOptions(options))
               .startSpan();
     }
@@ -2072,7 +2075,7 @@ && getOptions().getOpenTelemetryTracer() != null) {
           getOptions()
               .getOpenTelemetryTracer()
               .spanBuilder("com.google.cloud.bigquery.BigQuery.queryWithTimeout")
-              .setAllAttributes(jobId != null ? jobId.getOtelAttributes() : null)
+              .setAllAttributes(jobId != null ? jobId.getOtelAttributes() : Attributes.empty())
               .setAllAttributes(otelAttributesFromOptions(options))
               .startSpan();
     }
@@ -2125,7 +2128,7 @@ && getOptions().getOpenTelemetryTracer() != null) {
           getOptions()
               .getOpenTelemetryTracer()
               .spanBuilder("com.google.cloud.bigquery.BigQuery.getQueryResults")
-              .setAllAttributes(jobId.getOtelAttributes())
+              .setAllAttributes(jobId != null ? jobId.getOtelAttributes() : Attributes.empty())
               .setAllAttributes(otelAttributesFromOptions(options))
               .startSpan();
     }