BUG: Fix formatting of complex numbers with exponents

[snitish]

• closes BUG: Printing of a pandas Series of complex numbers with e-notation has broken between 2.0.x and older versions and the newer 2.1.x, 2.2.x versions #60393
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added an entry in the latest doc/source/whatsnew/v3.0.0.rst file if fixing a bug or adding a new feature.

>>> input_array=[(1.8816e-09+0j), (3.39676e-09+0j)]
>>> pd.Series(input_array)
0    1.881600e-09+0.000000e+                    00j
1    3.396760e-09+0.000000e+                    00j
dtype: complex128

The issue was due to the regex in the _trim_zeros_complex function not being able to handle +/- in the exponent. It assumes the complex number string to be of the form (-)xxx(+/)yyyj. I fixed the regex so it doesn't split on +/- if preceded by an exponent.
Post the fix:

>>> input_array=[(1.8816e-09+0j), (3.39676e-09+0j)]
>>> pd.Series(input_array)
0    1.881600e-09+0.000000e+00j
1    3.396760e-09+0.000000e+00j
dtype: complex128

[snitish]

@mroeschke Thanks for your feedback on #60405. Raised a new PR with amendments.

[mroeschke]

Thanks @snitish