fix(v2): fix svg loader for CSS files

[apurvaojas]

Motivation

Fixes SVG used in CSS

fix #3964

Have you read the Contributing Guidelines on pull requests?

yes

Test Plan

preview

[netlify]

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[github-actions]

Size Change: +12 B (0%)

Total Size: 155 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/blog/2017/12/14/introducing-docusaurus/index.html	20.7 kB	+1 B (0%)
website/build/docs/introduction/index.html	180 B	0 B
website/build/index.html	5.82 kB	+3 B (0%)
website/build/main.********.js	111 kB	+8 B (0%)
website/build/styles.********.css	17.6 kB	0 B

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[slorber]

Thanks @apurvaojas

Your code does not pass CI checks and breaks other things, but will edit your PR and merge this useful fix.
TIL about the issuer attribute ;)

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟢 Performance	92
🟢 Accessibility	99
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-3965--docusaurus-2.netlify.app/classic/