I think this is overthinking things. I just tested using the official X app on my iPhone and the predictive text suggestions always use the curly apostrophe, and if I manually type the characters for "I've" it automatically puts in the curly one too. If you want to manually type the straight apostrophe you have to go out of your way to hold down on the apostrophe button on the keyboard and select the straight apostrophe alternative. If she typed that tweet from her iPhone then she would have to go out of her way to type it without a curly apostrophe. I assume Android works the exact same way. I think the tweet is sketchy but I don't think this why.
while the ` ' argument was kinda retarded, and already debunked, that tweet was not written by an english speaker. "I just got back access to my phone yesterday" sounded like she anal raped her phone. And that wasn't the only grammar error in the tweet
Apostrophe - Wikipedia
en.wikipedia.org
Probably just autistic over-analysing, but it's there.