standalone: fix double <h1> and padding on select2 drops dev/core#4831

[artfulrobot]

Fixes https://lab.civicrm.org/dev/core/-/issues/4831 and also fixes problem introduced by #28471 that doubled the <h1> on angularjs pages.

Before:

Now:

[civibot]

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[artfulrobot]

@colemanw I've tagged you on this because it touches the angular code for identifying the "cms" page title.

[artfulrobot]

@colemanw ok the updated pr

• uses your suggestion on the union CSS selector, but also rewrites that whole bit in plain ol' JS because it's 2023 and we don't need to use two libraries to do that anymore. The new code is clearer to read (I think); slightly fewer bytes; and undetectably faster/more green.
• Renamed a var containing HTML to make it clear that it contains HTML not a plain text.
• removes the <del> bit - not needed, still works for deleted contacts.
• cleans up the rule in the css.

[artfulrobot]

I've tested in D10 (to check I hadn't broken previous behaviour) and standalone.

[colemanw]

Great work, thanks Rich & sorry for all the nitpickyness.

[artfulrobot]

@colemanw thanks for the merge, that messed up select2 padding was really annoying me! no worries about nitpickiness, a lot of standalone is still a mix of "I put this random code in here and it sort of worked" and better new code, so always good to question.

[colemanw]

Yea @artfulrobot I think some of the standalone templates were copied back from an ancient version of Civi so lots of outdated things to fix up.