chat: fix comparison of prerelease versions

[cebtenzzre]

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Ordering before this PR (not deterministic, but this is one possibility):

foob
fooa
foo
2.0
2.0.0 (greater than 2.0)
2.0.99-rc1
2.0.99-rc10
2.0.99-rc11
2.0.99-rc2
2.0.99-rc20
2.0.99
2.1.0-rc1
2.1.0
3.0.0
3.0.0-dev0
3.0.1
3.0.1-dev0
3.0.1-dev1
3.1.0
4.1.0

Ordering after this PR:

foo
fooa
foob
2.0.0
2.0 (equal to 2.0.0)
2.0.99-rc1
2.0.99-rc2
2.0.99-rc10
2.0.99-rc11
2.0.99-rc20
2.0.99
2.1.0-rc1
2.1.0
3.0.0-dev0
3.0.0
3.0.1-dev0
3.0.1-dev1
3.0.1
3.1.0
4.1.0

The order is now deterministic as it never ignores any part of the version. Pre-release versions compare as less than the stable releases that come after. This means we shouldn't use post-release suffixes (e.g. v3.1.1-web_search_beta_2 after v3.1.1) unless we can agree on what pre-release and post-release suffixes look like (maybe -dev and -rc are the only pre-release suffixes?)

This PR also fixes an assertion failure caused by the combination of #2759 and #2762.