* fix#4257 fixed ui for mermaid diagrams in dark mode
* fixed linting issues
* added dynamic color theme for mermaid diagrams
* now mermaid block uses theme according to the system as well when 'follow system' is selected
* refactored code for mermaid theme logic
* refactored mermaid code to use const instead of function call
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Co-authored-by: root <root@DESKTOP-G3MCU14>