fix: resolve to task instead of run in addon instructions for deno

[brunnerh]

Set up a project earlier and it output:

Run deno run db:push to update your database schema

...which is wrong for deno.

package-manager-detector seems to be used in other spots for this, so I added it here as well.
Tried to find all places using run, but only found it in lucia & drizzle.

---

Regarding changesets, I found this statement in CONTRIBUTING.md a bit confusing:

Only publish a change set if it is in 'sv' or 'svelte-migrate' as all other packages are bundled.

The changes are in addons but it affects sv...

[changeset-bot]

🦋 Changeset detected

Latest commit: 7972974

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 0 packages

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[pkg-pr-new]

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npx https://pkg.pr.new/sveltejs/cli/sv@599

npx https://pkg.pr.new/sveltejs/cli/svelte-migrate@599

commit: 7972974

[manuel3108]

Totally makes sense, thank you!