[Fix] Squeeze y_values in signal_interpolate

[janwodnicki]

Description

Fixing issue #1025: Missing np.squeeze for y_values when it is pands.series

Proposed Changes

Converted y_values to numpy array and squeezing in signal_interpolate.
Merged isinstance calls to fix pylint R1701 error.

Checklist

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• I ran the CODE CHECKS on the files I added or modified and fixed the errors.
• I have added the newly added features to News.rst (if applicable)

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[DominiqueMakowski]

Nice one @janwodnicki! thanks :)

[welcome]

Congrats on merging your first pull request! 🎉🍾 We're looking forward to your next one!