Upgrade TinyMCE from 5.8.2 to 5.10.2

[Dianne Tennent]

https://www.tiny.cloud/blog/new-release-tinymce-5-10/

    An upgrade to our Dom API to enhance URL security
    Adding user-friendly enhancement to our VK API
    Added ability for engineers to turn off deprecation console warning messages
    Upgrades to our element API, relating to scrolling

https://www.tiny.cloud/docs/release-notes/release-notes510/
Security fixes

TinyMCE 5.10 provides fixes for the following security issues.

Fixed URLs not cleaned correctly in some cases in the link and image plugins. This caused a medium severity Cross Site Scripting (XSS) vulnerability. Tiny Technologies would like to thank Yakir6 for discovering this vulnerability.

[Mahara Bot (dev-mahara)]

Patch for "main" branch: https://reviews.mahara.org/12465

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/12466
Committed: https://git.mahara.org/mahara/mahara/commit/b6a03981fba1a7efe8a9e82008ace3a9924c757e
Submitter: Robert Lyon (<email address hidden>)
Branch: main

commit b6a03981fba1a7efe8a9e82008ace3a9924c757e
Author: Doris Tam <email address hidden>
Date: Tue Aug 24 13:14:29 2021 +1200

Bug 1962805 - TinyMCE customisation: Mathslate

Reapplied from https://reviews.mahara.org/#/c/11943/
Bug 1940615

Change-Id: Ic6a6ea3104af15005d8363c2eff147ede0426249

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/12467
Committed: https://git.mahara.org/mahara/mahara/commit/70496e906be7f790b3f9b70cda5c1c3eea6f8cce
Submitter: Robert Lyon (<email address hidden>)
Branch: main

commit 70496e906be7f790b3f9b70cda5c1c3eea6f8cce
Author: Doris Tam <email address hidden>
Date: Tue Aug 24 14:42:57 2021 +1200

Bug 1962805 - TinyMCE customisation: Restrict heading levels on mobile for accessibility

Reapplied this patch: https://reviews.mahara.org/#/c/11946/4
Bug 1940615

Updated tinymce/readme.mahara version number to 5.10.2

Change-Id: I1364d3fb882993123b794215562bb20109d600f5

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/12465
Committed: https://git.mahara.org/mahara/mahara/commit/b7135e1cdc8de8743c7733b19089ede231f26412
Submitter: Robert Lyon (<email address hidden>)
Branch: main

commit b7135e1cdc8de8743c7733b19089ede231f26412
Author: Dianne Tennent <email address hidden>
Date: Fri Mar 4 10:23:09 2022 +1300

Bug 1962805: Upgrade TinyMCE from 5.8.2 to 5.10.2

Change-Id: Ia4ff0be3fb1627be95be825299b9def63807454f