No, both come from Proto-Semitic ʔil- (
https://en.wiktionary.org/wiki/Reconstruction:Proto-Semitic/%CA%94il-). In the ancient religion of the western Near East, El was the chief diety (
https://www.britannica.com/topic/El). El, Elohim, and YHWH were also names for the Israelite God. Islam was informed from Judaism and Christianity, both of which were present in the Arabian Peninsula, but the words for God in Arabic and Hebrew are similar simply because the two languages are related - “cousins” in the Semitic family tree. There is no reason to think that "Allah" derived from "El." Similarity doesn't necessarily mean derivation. Just because they are similar doesn't mean one came from the other.