the antecedent of قمره in the phrase refers to the spring. It is as though it tells that the husband represents a "night" during a spring season and that his wife is the "moon" shining throughout the spring season.

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Note added at 18 hrs (2020-09-15 10:50:32 GMT)
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By all means, be my guest any time! The remainder of the phrase can be rendered as follows:
…who has taken [to wife] the joy of the eye, May Allah prolong his life.


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Note added at 1 day 19 hrs (2020-09-16 12:11:57 GMT)
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The "take" here is meant to be used as an optimal approximation and reflection of the Arabic verb "أخذ" in as far as its connotations imply; especially for the fact that one of the uses of "take" as a phrasal verb means to marry, e.g. attached.
Added to that I have just realized that there is a very delicate and subtle double meaning in the structure of the whole phrase in which the “congratulations” is not only meant for the husband who has “taken the apple of the eye”, it rather applies to the wife who has “taken the apple of the eye”. We can discover this subtlety evident at the beginning of the phrase, as it conveys the best wishes to both and not just for one of them. It says, in a rough rendering:
Congratulations to the wedding of both, a spring season together with its shinning moon; each having taken the joy of the eye, May Allah prolong the life of both. (Contrary to what I mistakenly proposed, “May Allah prolong his life”.
In Arabic "عمره" though its form indicates masculine antecedent, it practically refers to the dual noun “الاثنين”, this is in the one hand. Now if we look closely to the whole phrase, we cannot spot any masculine noun, preceding the relative pronoun “اللي “, and if we want to identify the noun to whom this pronoun refers, we can find that it refers to” ليلة ربيع وقمرة “, i.e. “a spring season and /together with its shinning moon”, which indicate the husband and the wife altogether.
I believe that the phrase as a whole was delicately coined in such a way that it intentionally expresses best wishes to the husband and the wife at the same time in the metaphor being used, i.e. “a spring season and its shinning moon”.


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Note added at 1 day 19 hrs (2020-09-16 12:15:37 GMT)
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correction:
"...it rather applies to the wife who has “taken the apple of the eye” as well...

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Note added at 1 day 20 hrs (2020-09-16 12:55:52 GMT)
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Sorry again, another correction:
"a night of a spring season", I missed including the "night", in the rough translation.