Fix QPY scoped cache uploads in GitHub Actions

[jakelishman]

When we consolidated the branch-protection rules¹, we removed the on: push logic from all the jobs too, to avoid duplication of unnecessary work. This has the knock-on effect of preventing the QPY cache from getting populated into a cache scope² that's reachable from later PRs and the merge queue, and so all the QPY jobs have been taking a lot longer than necessary recently.

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I'm not entirely confident in this, but it's hard to check without merging to main.

AI/LLM disclosure

• I didn't use LLM tooling, or only used it privately.
• I used the following tool to help write this PR description:
• I used the following tool to generate or modify code:

Footnotes

1. 913091b: Unify GitHub Actions branch-protection run logic (Unify GitHub Actions branch-protection run logic #15794) ↩

2. https://docs.github.com/en/actions/reference/workflows-and-actions/dependency-caching#restrictions-for-accessing-a-cache ↩

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core
• @mtreinish

[coveralls]

Coverage Report for CI Build 26651179134

Coverage increased (+0.01%) to 87.526%

Details

• Coverage increased (+0.01%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 15 coverage regressions across 4 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

15 previously-covered lines in 4 files lost coverage.

File	Lines Losing Coverage	Coverage
crates/qasm2/src/parse.rs	6	97.15%
crates/circuit/src/parameter/symbol_expr.rs	5	74.13%
crates/qasm2/src/lex.rs	3	92.29%
crates/circuit/src/parameter/parameter_expression.rs	1	91.04%

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Coverage Stats

Relevant Lines:	123926
Covered Lines:	108467
Line Coverage:	87.53%
Coverage Strength:	963077.39 hits per line

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💛 - Coveralls

[jakelishman]

Wait, I'm actually not sure what happens here if the required inputs from the workflow_call aren't present. I need to check that and probably think about an alternative strategy.