added paddle.sum frontend and test for it

[sabre-code]

Added paddle.sum frontend function. Wrote tests for it.

Fixes #22770

[github-actions]

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[sabre-code]

@yopknopixx hello please review my PR.

[shubhamb-22]

@sabre-code I see a lot of new failures introduced by your PR. https://github.com/unifyai/ivy/actions/runs/6021337957?pr=22771

[sabre-code]

@shubhamb-22 I guess they are from some other functions. Can you check code.

[sabre-code]

@shubhamb-22 Please guide with possible issue. This is my first PR here.

[yopknopixx]

@sabre-code I will go through it shortly

[sabre-code]

@sabre-code I will go through it shortly

@yopknopixx hello, did you check code, do I need to change anything. Please let me know if there is anything. :)

[yopknopixx]

What is the reason for doing this?

[sabre-code]

@yopknopixx the paddle documentation says if the dtype of input array is int32 the output dtype should be int64. ivy.sum does not cover this edge case and if this dtype conversion is not done all tests fail with "expected dtype int64 got int32". to address this issue this is done. Thanks

[sabre-code]

@yopknopixx I rechecked and found that even when input array dtype is bool paddle.sum converts it to int64, I have added condition for that too. and ivy.sum documentation says whenever such expected dtype is different from dtype of array we have to convert the dtype to desired type before passing to the function. so added code to do that too.

[Omar88magdy]

hey sabre-code,
i want to inform you that i've been working on (sum) function before you and i 've already implemented it.
thank you.

[yopknopixx]

Hi @sabre-code ,

Thanks for the PR!
However, since there is an earlier PR for the issue, I will be closing this one. Given that you have completed the implementation, you can submit this PR as part of the application process.

Thanks!