Make number slider more robust against weird input values

[philippotto]

This is a workaround for layer opacity values which become undefined in some circumstances. The actual cause for this is unknown to me, but making the number slider more robust should be an okay way to tackle this.

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

• I patched the code locally so that undefined is passed to the number slider and it worked as expected. One can also test it by using the front-end api to set an undefined opacity, but I think it's not crucial to reproduce this. A review should be sufficient.

Issues:

• workaround for Guard against corrupted settings #4751

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• Updated (unreleased) changelog
• Updated (unreleased) migration guide if applicable
• Updated documentation if applicable
• Adapted wk-connect if datastore API changes
• Needs datastore update after deployment
• Ready for review

[MichaelBuessemeyer]

I just tried to find the bug myself and found out that the NumberInput isn`t validated good enough.

Just typing an empty string into the numberfield and then defocusing the browsers window crashes wk.

A possible solution is adding _.isNumber(_value) to the if check in line 27. This should make sure, that no none number value is saved as a number setting.

That way your workaround might not be necessary.

What do you think about this solution @philippotto?

[philippotto]

I also added a validation check to the onblur code. Thanks for finding this bug, @MichaelBuessemeyer 🙏

[MichaelBuessemeyer]

LGTM 🎉