Support VerseRefs with segments across versifications

[Enkidu93]

Includes:

• Add test to cover alignment of verses across versifications with segments (e.g., a,b,c...).
• Strip segments when converting/comparing refs with verse segments across versifications because VerseRef does not support it properly

This fixes an issue Michael recently brought up on slack: https://sil-language-software.slack.com/archives/C06A8JFBU5S/p1778328868601589. (I can create a retroactive issue if you would like). I decided to prioritize this because depending on the problem, it could be causing catastrophic misalignment - especially for silnlp - and it was in this case.

The root of this problem is that ChangeVersification() (and by extension VerseRef.CompareTo()) exhibit very odd behavior when working with verse segments. Basically,

var vrS = new VerseRef("NUM 17:1a", ScrVers.Original);
var vr = new VerseRef("NUM 17:1", ScrVers.Original);

vrS.ChangeVersification(ScrVers.English);
vr.ChangeVersification(ScrVers.English);

// Now
// vr == new VerseRef("NUM 16:36", ScrVers.English) :heavy_check_mark: 
// but 
// vrS == new VerseRef("NUM 17:1a", ScrVers.English) :exploding_head: 

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This change is