fix(core): App should not crash with a custom rest endpoint

[netroy]

fixes #5880

[github-actions]

Great PR! Please pay attention to the following items before merging:

Files matching packages/**:

• If fixing bug, added test to cover scenario.
• If addressing forum or Github issue, added link to description.

Files matching packages/**/*.ts:

• Added unit tests to cover new or updated functionality.

Make sure to check off this list before asking for review.

[codecov]

Codecov Report

Patch coverage: 45.45% and no project coverage change.

Comparison is base (dba5be3) 17.52% compared to head (9b4acaa) 17.52%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5911   +/-   ##
=======================================
  Coverage   17.52%   17.52%           
=======================================
  Files        2495     2495           
  Lines      114289   114289           
  Branches    17852    17852           
=======================================
  Hits        20027    20027           
  Misses      93671    93671           
  Partials      591      591           

Impacted Files	Coverage Δ
packages/cli/src/Server.ts	0.00% <0.00%> (ø)
packages/cli/src/commands/start.ts	0.00% <0.00%> (ø)
packages/editor-ui/src/stores/n8nRootStore.ts	70.90% <57.14%> (+1.61%)	⬆️
packages/editor-ui/src/Interface.ts	100.00% <100.00%> (ø)

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[github-actions]

✅ All Cypress E2E specs passed

[janober]

Got released with [email protected]