Big image "data:" src breaks import

[catalan-adobe]

Description
Pages with big data:image/... (~2MB) break import flow

To Reproduce
Steps to reproduce the behavior:

1. Clone https://github.com/aemysites/nichols5973-250718
2. aem import
3. Import URL https://www.russellreynolds.com/en/about/who-we-are/sustainability with default parameters
4. See error SyntaxError: Invalid regular expression: ...

Expected behavior
Import should not break

Versions:
@adobe/helix-importer-ui@1.57.7
@adobe/aem-cli@16.10.32 (latest: 16.10.43)

Additional context

Issue occurs in replaceSrcInMarkdown https://github.com/adobe/helix-importer/blob/main/src/utils/MDUtils.js#L14-L20 <= This function is about converting relative URLs into absolute.
This is not needed for data|blob src.