fix(core): Bring back execution data on the executionFinished push message

[netroy]

Summary

We removed the full execution data from the payload for executionFinished push message in #11703, because that serialization sometimes required quite a lot of memory.
This PR "temporarily" brings that data back, but now we instead serialize the data using flatted.stringify instead of JSON.stringify, which is a lot less expensive.

This change is still temporary, as we should instead improve the state management in the frontend to construct the final execution data based on all the partial data already delivered in the nodeExecuteAfter push messages.

Related Linear tickets, Github issues, and Community forum posts

PAY-2270

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)

[codecov]

Codecov Report

Attention: Patch coverage is 41.66667% with 14 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ges/editor-ui/src/composables/usePushConnection.ts	47.05%	9 Missing ⚠️
...ckages/cli/src/workflow-execute-additional-data.ts	16.66%	5 Missing ⚠️

📢 Thoughts on this report? Let us know!

[github-actions]

⚠️ Some Cypress E2E specs are failing, please fix them before merging

[cypress]

n8n    Run #8031

Run Properties:   Failed #8031  •  f8674126cc: 🌳 🖥️ browsers:node18.12.0-chrome107 🤖 netroy 🗃️ e2e/*

Project	n8n
Branch Review	PAY-2270-temporary-fix
Run status	Failed #8031
Run duration	07m 24s
Commit	f8674126cc: 🌳 🖥️ browsers:node18.12.0-chrome107 🤖 netroy 🗃️ e2e/*
Committer	कारतोफ्फेलस्क्रिप्ट™
View all properties for this run ↗︎

---

Test results
Failures	6
Flaky	0
Pending	0
Skipped	0
Passing	319
View all changes introduced in this branch ↗︎

---

Tests for review

  30-langchain.cy.ts • 5 failed tests

View Output Video

Test		Artifacts
Langchain Integration > should be able to open and execute Basic LLM Chain node		Screenshots Video
Langchain Integration > should be able to open and execute Agent node		Screenshots Video
Langchain Integration > should add and use Manual Chat Trigger node together with Agent node		Screenshots Video
Langchain Integration > should show tool info notice if no existing tools were used during execution		Screenshots Video
Langchain Integration > should not show tool info notice if tools were used during execution		Screenshots Video

  19-execution.cy.ts • 1 failed test

View Output Video

Test		Artifacts
Execution > should execute workflow partially up to the node that has issues		Test Replay Screenshots Video

  14-data-transformation-expressions.cy.ts • 0 failed tests

View Output

Test		Artifacts

  14-mapping.cy.ts • 0 failed tests

View Output

Test		Artifacts

  9-expression-editor-modal.cy.ts • 0 failed tests

View Output

Test		Artifacts

The first 5 failed specs are shown, see all 45 specs in Cypress Cloud.