Fix unbound local error in online_cnmf when use_corr_img is true but is1p is false

[ethanbb]

Description

Currently, in the method OnACID._prepare_object , d1 and d2 are only set when self.is1p is true, but are only used if the parameter online['use_corr_img'] is true. I was trying to run it with use_corr_imgbut without setting the other parameters in a way that causesis1p` to be true, so I got an unbound local error.

Since these variables are only used in one place in this function, I just moved the line that defines them to be right before they are used. I'm not 100% sure the functionality is correct, but the line just reads from estimates.dims, which seems pretty straightforward.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Has your PR been tested?

Did not run the tests myself (relying on CI) but I did check that making this change prevented the error I was getting when trying to call fit_online with these parameters.