fix callback block rename from UI

[BobbyWang0120]

Summary

• Fix callback block rename from the pipeline editor UI.
• Use the editor's full block state when saving from the configure-block modal so callback blocks are included in the save payload.

Fixes #6110

Root cause

Callback blocks are stored separately from regular pipeline blocks. The rename modal was saving with only pipeline.blocks, so callback blocks were missing from the data that savePipelineContent uses to build the callbacks payload.

Validation

• Verified manually in the browser that renaming a callback block from the UI now works.
• Ran git diff --check.
• Focused frontend lint was not run locally because mage_ai/frontend/node_modules is not installed in this checkout, so next is unavailable.

Demo

mage-6110-callback-rename-demo.mp4