fix: false positives for custom-element with svelte v3 in `svelte/valid-compile`

[ota-meshi]

fixes #602

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🦋 Changeset detected

Latest commit: 60a56e4f4a01bc152cf192af5a123c2f7ab1d92b

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

This PR includes changesets to release 1 package

| Name | Type | | -------------------- | ----- | | eslint-plugin-svelte | Patch |

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