ENH Use cached table list from ClassInfo

[lekoala]

Description

Fixes #563

Using ClassInfo::hasTable, the cached data is used and avoid extra query per request

Manual testing steps

Install debugbar
Install subsite module
Check that no extra query is made

Issues

• Middleware should not make table check on each request #563

Pull request checklist

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• This change is covered with tests (or tests aren't necessary for this change)
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[GuySartorelli]

Please retarget to 3 and tick the relevant checkboxes if this is ready for review.

[GuySartorelli]

LGTM

[GuySartorelli]

Ahh, there's a merge conflict - can you please resolve that?

[lekoala]

ok should be good now

[GuySartorelli]

The merge commit isn't ideal but I'll make sure to squash and merge so it should be fine.
Thanks for doing this.