Tooltip integer fix

[mrvisscher]

Fixes a bug with the previous table overflow tooltip functionality where an error is thrown when the table cell data iss not of type String.

Checklist

• Keep pull requests small so they can be easily reviewed.
• Update the documentation, please follow the numpy style guide.
• Update tests.
• Categorize the PR by setting a good title and adding one of the labels:
  bug, feature, ui, change, documentation, breaking, ci
  as they show up in the changelog.
• Link this PR to related issues by using closing keywords.
• Request a review from another developer.

[coveralls]

coverage: 50.055%. remained the same
when pulling c4bbde2 on mrvisscher:tooltip-integer-fix
into d5b9e75 on LCA-ActivityBrowser:master.

[marc-vdm]

Could you check if this works in combination with #1151 and we get a useful date value and not a Unix time string or something?

[github-actions]

This issue has been implemented in the new release of Activity Browser 🚀 (version 2.9.3), you can get the new version by updating Activity Browser.

🤖beep boop! I'm a bot and this message was an automated action. If updating does not make sense for this issue, just ignore this.