Add a _search_ads function case for when ADS cannot find doi for a publication

[lesliech1004]

The _search_ads function in publications.py crashes when ADS cannot find a doi code for a publication when only provided a bibcode or reference name.

Error when trying to ingest this publication:
[Faherty+2022]
https://ui.adsabs.harvard.edu/abs/2022BAAS...54e.224F/abstract
Source: WISE J124332.17+600126.6