fix(@angular-devkit/build-angular): use url function lexer to rebase Sass URLs

[clydin]

When rebasing URLs found within Sass files (sass/scss), the previous regular expression based searching has been replaced with a lexer that scans the Sass files for CSS url() functions and extracts URL values. This change allows for more accurate discovery of URLs as well as reducing the amount of content traversals per file. The lexer logic is based on CSS Syntax Module Level 3 (https://www.w3.org/TR/css-syntax-3/).

Fixes #24245