fix: display slide import errors in client

[AlbertBrand]

While debugging some other issue, it appeared that error messages were consumed in some scenarios. This PR adds error logging to the console when the cached slide import fails, making it easier for others to debug their issues.

[netlify]

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[pkg-pr-new]

commit: 825e71d

create-slidev

pnpm add https://pkg.pr.new/slidevjs/slidev/create-slidev@1816

@slidev/client

pnpm add https://pkg.pr.new/slidevjs/slidev/@slidev/client@1816

create-slidev-theme

pnpm add https://pkg.pr.new/slidevjs/slidev/create-slidev-theme@1816

@slidev/parser

pnpm add https://pkg.pr.new/slidevjs/slidev/@slidev/parser@1816

@slidev/cli

pnpm add https://pkg.pr.new/slidevjs/slidev/@slidev/cli@1816

@slidev/types

pnpm add https://pkg.pr.new/slidevjs/slidev/@slidev/types@1816

Open in Stackblitz

[KermanX]

Thanks!