chore(deps): upgrade gapic-generator-java to 2.8.0 and update gax-jav…

…a to 2.18.1 (#19)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 450543911

Source-Link: googleapis/googleapis@5528344

Source-Link: https://github.com/googleapis/googleapis-gen/commit/9f6775cab1958982b88967a43e5e806af0f135db
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiOWY2Nzc1Y2FiMTk1ODk4MmI4ODk2N2E0M2U1ZTgwNmFmMGYxMzVkYiJ9

java-bigquery-data-exchange/google-cloud-bigquery-data-exchange/src/main/java/com/google/cloud/bigquery/dataexchange/v1beta1/AnalyticsHubServiceClient.java

@@ -136,7 +136,6 @@ public static final AnalyticsHubServiceClient create(AnalyticsHubServiceSettings
    * Constructs an instance of AnalyticsHubServiceClient, using the given stub for making calls.
    * This is for advanced usage - prefer using create(AnalyticsHubServiceSettings).
    */
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public static final AnalyticsHubServiceClient create(AnalyticsHubServiceStub stub) {
     return new AnalyticsHubServiceClient(stub);
   }
@@ -151,7 +150,6 @@ protected AnalyticsHubServiceClient(AnalyticsHubServiceSettings settings) throws
     this.stub = ((AnalyticsHubServiceStubSettings) settings.getStubSettings()).createStub();
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   protected AnalyticsHubServiceClient(AnalyticsHubServiceStub stub) {
     this.settings = null;
     this.stub = stub;
@@ -161,7 +159,6 @@ public final AnalyticsHubServiceSettings getSettings() {
     return settings;
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public AnalyticsHubServiceStub getStub() {
     return stub;
   }

java-bigquery-data-exchange/google-cloud-bigquery-data-exchange/src/main/java/com/google/cloud/bigquery/dataexchange/v1beta1/stub/AnalyticsHubServiceStubSettings.java

@@ -409,7 +409,6 @@ public UnaryCallSettings<SetIamPolicyRequest, Policy> setIamPolicySettings() {
     return testIamPermissionsSettings;
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public AnalyticsHubServiceStub createStub() throws IOException {
     if (getTransportChannelProvider()
         .getTransportName()