[APV] Avoid allocate textures only used with SH2 if using SH1 + Display approx amount of vmem used by APV

[FrancescoC-unity]

So up until now we were always allocating textures used by APV as if SH2 was always used; now we only allocate them only when actually needed.

I also added a small info box to show how much is allocated for the APV

[github-actions]

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[github-actions]

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