[stable31] fix(userconfig): ConfigLexiconEntry for locale

[pako81]

Related to #54080 and #54082

Currently, changing user's locale leads to conflict between new type (mixed) and old type (string). Only needed for 31 as 32 has already the changes in place.

[susnux]

(should be available in master already?)

[pako81]

Would it be possible to have this in 31.0.14? :) Thanks

[github-actions]

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