Add project-template-24.svg, project-template-16.svg

[gavinmn]

closes https://github.com/github/primer/issues/1744

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 537c500240d39ecda51ec767e745b916a0ce22bc

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

This PR includes changesets to release 1 package

| Name | Type | | ---------------- | ----- | | @primer/octicons | Minor |

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