It says Shemos 8,22:
הֵ֣ן נִזְבַּ֞ח אֶת־תּֽוֹעֲבַ֥ת מִצְרַ֛יִם לְעֵֽינֵיהֶ֖ם וְלֹ֥א יִסְקְלֻֽנוּ׃ (...)
"(...) If we sacrifice the god of the the Egyptians won't they stone us?" (Translation based on Rashi and Onklus)
Rashi on Vayikra 1,2 - with regards to what qualifies as a korban that one can bring - quoting Sifri says:
מן הבקר" - להוציא את הנעבד" -"from the cattle" to exclude a worshipped animal.
How could they sacrifice korban pesach in Egypt if it was served as a deity? Was there an exemption here to bring a worshipped animal or am I misunderstanding the Parsha? please answer with sources.