Update bundled jQuery to version 3.5.1

[wenz]

The repository contains several instances of jQuery 3.4.1 (due to the fix for issue #20001).
jQuery 3.5.0 was released last month, which also fixed two security vulnerabilities (CVE-2020-11022 & CVE-2020-11023).
However, jQuery 3.5.0 came with a regression affecting many other JavaScript libraries (cf. https://blog.jquery.com/2020/05/04/jquery-3-5-1-released-fixing-a-regression/). jQuery 3.5.1 fixes that regression, so this version is fit to use for us.

PR is coming up later today ...

[mkArtakMSFT]

Thanks @wenz.
We will review the PR in approximately a week and will continue the conversation there.