Is "take" used frequently as the meaning of "believe" or "think"?
Answer from a Native speaker
"I take it" is an informal expression that is often used when you say something that is likely true, and you are in the process of confirmation. It has a similar meaning to "believe" or "think," although this is based on nuance only and not the definition. When the speaker says "I take it you're an art lover," this is meant to be a question confirming what he believes to be true - that Gru is an art lover. Ex: Nice cat shirt! I take it you like cats? Ex: Looks like you're super sick. I take it you won't be going to work tomorrow?