fix: build-push-docker layer caching

[erikburt]

Fixes build-push-docker caching setup and optimizes ctf-build-image's usage of it.

Changes

build-push-docker

• Actually just fix caching, was completely broken before
• Default restore cache to false (there were no usages of these cache parameters anywhere, so this should have no effect)
• Rework the cache-to/cache-from inputs so they:
  • Are now defaulted in the shell script if cache restore/save is enabled
  • don't modify the parameters as it complicates it, let the caller fully choose the cache-to/cache-from
• Update to latest docker/build-push-action v7.0.0 (node24)

ctf-build-image

• pass proper caching configuration to build-push-docker

Testing

smartcontractkit/chainlink#21700

• https://github.com/smartcontractkit/chainlink/actions/runs/23559406257?pr=21700

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DX-3570