Update launchpad docs to build without failing

[clevinson]

As a prerequisite for having multiple versions of docs deployed on docs.cosmos.network, we need launchpad docs to compile properly.

Currently when building from the launchpad/backports branch, docs failed to compile. This fixes that by updating themeConfig in .vuepress/config.json as well as updating the package.json for docs to pull from the most recent cosmos vuepress theme.

Unblocks #7413

ref #6953

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• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[ethanfrey]

I didn't test this, but I can ensure this has no negative effects on the go code. If these docs work better for deployment, then I give a 👍

[alessio]

Great stuff. Approved.