fix(core): Preserve Data Collection on null setter

Ignore null assignments so the always-present Data Collection configuration and its current values remain intact.

Refs #5666

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry/src/main/java/io/sentry/SentryOptions.java

@@ -1715,7 +1715,9 @@ public void setSendDefaultPii(boolean sendDefaultPii) {
    * <p>Passing an empty {@link DataCollection} opts into the documented data-collection defaults.
    */
   public void setDataCollection(final @NotNull DataCollection dataCollection) {
-    this.dataCollection = dataCollection;
+    if (dataCollection != null) {
+      this.dataCollection = dataCollection;
+    }
   }
 
   /**

sentry/src/test/java/io/sentry/SentryOptionsTest.kt

@@ -67,6 +67,21 @@ class SentryOptionsTest {
     assertThat(options.dataCollection.userInfo).isFalse()
   }
 
+  @Test
+  fun `setting null data collection preserves the current instance`() {
+    val options = SentryOptions()
+    val dataCollection = DataCollection().apply { setUserInfo(false) }
+    options.dataCollection = dataCollection
+
+    SentryOptions::class
+      .java
+      .getMethod("setDataCollection", DataCollection::class.java)
+      .invoke(options, null)
+
+    assertThat(options.dataCollection).isSameInstanceAs(dataCollection)
+    assertThat(options.dataCollection.userInfo).isFalse()
+  }
+
   @Test
   fun `when options is initialized, logger is not null`() {
     assertNotNull(SentryOptions().logger)