fix(core): Preserve mutable breadcrumb data access

Initialize the lazy breadcrumb data map when callers request the full map. This keeps getData() mutable for existing callers while preserving lazy allocation for breadcrumbs that only serialize or read individual values.

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

Author: adinauer

sentry/src/main/java/io/sentry/Breadcrumb.java

@@ -629,7 +629,7 @@ public void setType(@Nullable String type) {
   @ApiStatus.Internal
   @NotNull
   public Map<String, Object> getData() {
-    return data;
+    return getOrCreateData();
   }
 
   /**

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

@@ -332,6 +332,15 @@ class BreadcrumbTest {
     breadcrumb.removeData(null)
   }
 
+  @Test
+  fun `getData returns mutable map for new breadcrumb`() {
+    val breadcrumb = Breadcrumb()
+
+    breadcrumb.data["k"] = "v"
+
+    assertEquals("v", breadcrumb.getData("k"))
+  }
+
   @Test
   fun `concurrent first writes keep all data entries`() {
     val breadcrumb = Breadcrumb()