feat: Relax client-side validation for BigQuery entity IDs

Removes client-side `checkArgument` and `checkNotNull` validations from the constructors of `TableId`, `DatasetId`, `RoutineId`, `ModelId`, and `ConnectionProperty`.

This change makes the client library more robust by preventing crashes when the server sends a response with unexpected null or empty values in these fields.

Author: jinseopkim0

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

@@ -82,8 +82,8 @@ public ConnectionProperty build() {
   }
 
   private ConnectionProperty(Builder builder) {
-    this.key = checkNotNull(builder.key, "Required key is null or empty");
-    this.value = checkNotNull(builder.value, "Required value is null or empty");
+    this.key = builder.key;
+    this.value = builder.value;
   }
 
   /** Return the key of property. */

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

@@ -43,7 +43,6 @@ public String getDataset() {
   }
 
   private DatasetId(String project, String dataset) {
-    checkArgument(!isNullOrEmpty(dataset), "Provided dataset is null or empty");
     this.project = project;
     this.dataset = dataset;
   }

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

@@ -62,8 +62,6 @@ public String getModel() {
   }
 
   private ModelId(String project, String dataset, String model) {
-    checkArgument(!isNullOrEmpty(dataset), "Provided dataset is null or empty");
-    checkArgument(!isNullOrEmpty(model), "Provided model is null or empty");
     this.project = project;
     this.dataset = dataset;
     this.model = model;

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

@@ -63,8 +63,6 @@ public String getRoutine() {
   }
 
   private RoutineId(String project, String dataset, String routine) {
-    checkArgument(!isNullOrEmpty(dataset), "Provided dataset is null or empty");
-    checkArgument(!isNullOrEmpty(routine), "Provided routine is null or empty");
     this.project = project;
     this.dataset = dataset;
     this.routine = routine;

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

@@ -71,8 +71,6 @@ public String getIAMResourceName() {
   }
 
   private TableId(String project, String dataset, String table) {
-    checkArgument(!isNullOrEmpty(dataset), "Provided dataset is null or empty");
-    checkArgument(!isNullOrEmpty(table), "Provided table is null or empty");
     this.project = project;
     this.dataset = dataset;
     this.table = table;