custom-preload does not work for Notebook 6.5.x

[echarles]

When using nbclassic 0.4.6 that contains #155, the notebook page fails to load with following errors in the browser console:

Failed to load resource: the server responded with a status of 404 (Not Found)
tree:1 Refused to execute script from 'http://localhost:8888/static/custom-preload.js?v=20221014081138' because its MIME type ('text/html') is not executable, and strict MIME type checking is enabled.
require.js?v=d37b48bb2137faa0ab98157e240c084dd5b1b5e74911723aa1d1f04c928c2a03dedf922d049e4815f7e5a369faa2e6b6a1000aae958b7953b5cc60411154f593:143 Uncaught Error: Script error for "custom-preload"
http://requirejs.org/docs/errors.html#scripterror
    at makeError (require.js?v=d37b48bb2137faa0ab98157e240c084dd5b1b5e74911723aa1d1f04c928c2a03dedf922d049e4815f7e5a369faa2e6b6a1000aae958b7953b5cc60411154f593:168:17)
    at HTMLScriptElement.onScriptError (require.js?v=d37b48bb2137faa0ab98157e240c084dd5b1b5e74911723aa1d1f04c928c2a03dedf922d049e4815f7e5a369faa2e6b6a1000aae958b7953b5cc60411154f593:1735:36)

Server log:

[W 08:11:42.992 NotebookApp] 404 GET /static/custom-preload.js?v=20221014081138 (::1) 1.260000ms referer=http://localhost:8888/tree
[W 08:11:48.233 NotebookApp] 404 GET /static/custom-preload.js?v=20221014081138 (::1) 1.260000ms referer=http://localhost:8888/tree

We need to fix that because for now notebook 6.5.1 pins to nclassic 0.4.5 as temporary workaround

cc @lneves12

[echarles]

cc/ @RRosio @ericsnekbytes

[lneves12]

Oh interesting, sorry. I am trying to understand why this broke the page, it should have been caught by the catch.

[echarles]

The error happens when you launch with jupyter notebook(not with jupyter nbclassic)

[echarles]

This is fixed with jupyter/notebook#6580

Closing.