ci: Streamline some caching

[mydea]

This streamlines some caching stuff for CI:

1. Extract dependency installation & cache out into a composite action for reusability
2. Updated the cache key for dependencies to only include package & dev-package package.json, not the E2E test ones.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser	22.5 KB (0%)
@sentry/browser (incl. Tracing)	34.85 KB (0%)
@sentry/browser (incl. Tracing, Replay)	71.18 KB (0%)
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	64.45 KB (0%)
@sentry/browser (incl. Tracing, Replay with Canvas)	75.53 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback)	88.17 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback, metrics)	90 KB (0%)
@sentry/browser (incl. metrics)	26.81 KB (0%)
@sentry/browser (incl. Feedback)	39.47 KB (0%)
@sentry/browser (incl. sendFeedback)	27.13 KB (0%)
@sentry/browser (incl. FeedbackAsync)	31.79 KB (0%)
@sentry/react	25.26 KB (0%)
@sentry/react (incl. Tracing)	37.83 KB (0%)
@sentry/vue	26.65 KB (0%)
@sentry/vue (incl. Tracing)	36.67 KB (0%)
@sentry/svelte	22.64 KB (0%)
CDN Bundle	23.73 KB (0%)
CDN Bundle (incl. Tracing)	36.49 KB (0%)
CDN Bundle (incl. Tracing, Replay)	70.81 KB (0%)
CDN Bundle (incl. Tracing, Replay, Feedback)	76.06 KB (0%)
CDN Bundle - uncompressed	69.61 KB (0%)
CDN Bundle (incl. Tracing) - uncompressed	108.27 KB (0%)
CDN Bundle (incl. Tracing, Replay) - uncompressed	219.52 KB (0%)
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	232.41 KB (0%)
@sentry/nextjs (client)	37.59 KB (0%)
@sentry/sveltekit (client)	35.45 KB (0%)
@sentry/node	115.61 KB (-0.1% 🔽)
@sentry/node - without tracing	90 KB (-0.12% 🔽)
@sentry/aws-serverless	99.42 KB (-0.1% 🔽)