I don't think we ate pigs even before Islam.
The Ethiopian Orthodox Christians don't eat it. A lot of neighbouring peoples had taboos against it even in Rwanda only very recently has pork been introduced. Islam in the Horn was preceded by Judaism and Christianity and both were anti-pork. In the Middle East, pork becomes rare after 1000BC
I don't know if some hunter gatherer people may have eaten meat from wild warthogs but besides that I don't think so.
From the fauna assemblages found all over the Somali peninsula during the Somali period (before Islam even), no warthog/bushpig was found. It is safe to say that our ancestors were always particular in excluding certain meat (some meat had exceptions at times like seafood and bird, only they were generally also within the taboo range, but not completely excluded like the pig).
Secondly, it is the nature of how the suids appeared. They surfaced in negligible quantities as a peripheral element through the consequence of hunting in the second phase and subsequent - mind you accompanying other animals also never eaten by geeljire before or after Islam. Those were caught through a hunting practice that was outsourced to specialized groups in Ethiopia and Somalis, and not even limited to distinct groups but often demographically small sub-groups within Cushitic, Omotic, and even Semitic, referred to as so-called "pollutants" that were eating "impure meat" - who had a dynamic where they would do specific work like go catch bovid for resources of hide, skin, etc., not for meat. If Somalis ate this, not only would you see this salient on our lands, but you would see an attempt at domestication because hunting is not something you suddenly pick up, neither do Somalis break food practice and subsistence ideology just for food they consider inferior in an area where other meat was abundant, especially when they were very particular in slaughtering halaal. As you rightly pointed out, the Christians in Ethiopia refrained from eating pig.
I have mentioned before that mixed-pastoral and hunting practices were incorporated at various times in the Somali peninsula during pre-Islamic days. However, when one observes the taxa data, the evidence never shows warthog or bushpig.