fixed errors in earth911 mock APIs

[rohit-yadavv]

fixes #224
I have fixed errors in earth911 mock APIs
updated res.send({ err: "invalid key" })to return res.send({ err: "invalid key" });

[lugenx]

thank you @rohit-yadavv, this issue is being reviewed. in the future, kindly ensure you first create an issue (if one doesn't already exist) before making changes. after creating the issue, please comment on it asking for assignment. this ensures your efforts align with the project's direction and prevents any potential wasted effort.

[vishwaszadte]

Thank you @rohit-yadavv
Please feel free to look at any other endpoints which may have the same issue and let us know.

[lugenx]

@vishwaszadte Since we haven't received a response, could you please review and either approve or reject it? Thank you.