fix: Address iframe height adjustment issues in Bluesky component

- Resolved bugs related to height adjustments for iframes by refining message handling logic.
- Improved the robustness of unique ID generation for iframe instances to prevent conflicts.
- Enhanced existing tests to cover new scenarios and ensure consistent behavior across multiple iframe instances.

Author: spences10

.changeset/famous-boats-sing.md

@@ -0,0 +1,14 @@
+---
+'sveltekit-embed': patch
+---
+
+feat: Enhance Bluesky component with unique iframe IDs and height
+adjustment logic
+
+- Implemented unique ID generation for each iframe instance to ensure
+  proper height updates.
+- Updated message handling to only adjust height for the specific
+  iframe that sent the message.
+- Added comprehensive tests to verify functionality for multiple
+  instances and edge cases, ensuring robustness in height adjustments
+  and iframe identification.