Fix: Fix npe for propagation url settings

src/main/java/io/jenkins/plugins/bitbucketpushandpullrequest/action/BitBucketPPRPullRequestServerAction.java

@@ -88,7 +88,7 @@ public BitBucketPPRPullRequestServerAction(@Nonnull BitBucketPPRPayload payload)
       }
     }
 
-    if (!globalConfig.getPropagationUrl().isEmpty()) {
+    if (globalConfig.isPropagationUrlSet()) {
       try {
         this.baseUrl = new URL(globalConfig.getPropagationUrl());
       } catch (MalformedURLException e) {

src/main/java/io/jenkins/plugins/bitbucketpushandpullrequest/config/BitBucketPPRPluginConfig.java

@@ -101,6 +101,10 @@
     return propagationUrl;
   }
 
+  public boolean isPropagationUrlSet() {
+    return !isEmpty(propagationUrl);
+  }
+
   @DataBoundSetter
   public void setNotifyBitBucket(@CheckForNull boolean notifyBitBucket) {
     this.notifyBitBucket = notifyBitBucket;

src/test/java/io/jenkins/plugins/bitbucketpushandpullrequest/action/BitBucketPPRPullRequestServerActionTest.java

@@ -21,6 +21,7 @@ public void testBaseUrlSet() {
                 BitBucketPPRPluginConfig.class)) {
             BitBucketPPRPluginConfig c = mock(BitBucketPPRPluginConfig.class);
             config.when(BitBucketPPRPluginConfig::getInstance).thenReturn(c);
+            when(c.isPropagationUrlSet()).thenReturn(true);
             when(c.getPropagationUrl()).thenReturn("https://example.org/scm/some-namespace/some-repo.git");
 
             BitBucketPPRPayload payloadMock = mock(BitBucketPPRPayload.class, RETURNS_DEEP_STUBS);

src/test/java/io/jenkins/plugins/bitbucketpushandpullrequest/processor/BitBucketPPRPullRequestServerPayloadProcessorTest.java

@@ -76,7 +76,6 @@ public void testProcessPayload() throws Exception {
         Mockito.mockStatic(BitBucketPPRPluginConfig.class)) {
       BitBucketPPRPluginConfig c = mock(BitBucketPPRPluginConfig.class);
       config.when(BitBucketPPRPluginConfig::getInstance).thenReturn(c);
-      when(c.getPropagationUrl()).thenReturn("");
 
       BitBucketPPRJobProbe probe = mock(BitBucketPPRJobProbe.class);