fix(ci): correctly install dependencies on cache-miss

[Stebalien]

Proposed Changes

Install build dependencies when building the FFI.

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[Stebalien]

Hm. Looks like this is getting rolled into #12423

[rvagg]

I think @rjan90 just has a test fix needed to get #12423 in and then this fix should be included there. We also need the FFI_PORTABLE=1 thing too to make it properly work.