fix: remove misleading metrics project mismatch log from getDatabaseClient

The log fired on every getDatabaseClient call even when metricsProjectId
was not explicitly set, producing noise. DatabaseId is not available at
build time so validation cannot move to SpannerOptions#build(). Since
the log is misleading rather than helpful, remove it entirely.

Author: RRap0so

java-spanner/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java

@@ -306,17 +306,6 @@ public DatabaseClient getDatabaseClient(DatabaseId db) {
       if (dbClients.containsKey(db)) {
         return dbClients.get(db);
       } else {
-        SpannerOptions opts = getOptions();
-        String metricsProject = opts.resolveMetricsProjectId();
-        if (opts.isEnableBuiltInMetrics()
-            && metricsProject != null
-            && !metricsProject.equals(db.getInstanceId().getProject())) {
-          logger.log(
-              Level.INFO,
-              "Built-in metrics project ''{0}'' differs from DatabaseId project ''{1}''."
-                  + " Use setMetricsProjectId() to override if needed.",
-              new Object[] {metricsProject, db.getInstanceId().getProject()});
-        }
         if (clientId == null) {
           clientId = nextDatabaseClientId(db);
         }