Map card: set "dark_mode" dependingly on theme mode

No change.

It seems that there might be a solution in at #20541 a few days ago.
Hope, that it works, because I am facing the same problem.

fixed in 2024.5

Default light theme:

Default dark theme:

  - type: horizontal-stack
    cards:
      - type: map
        entities: &ref_markers
          - person.abc
          - zone.abc

      - type: map
        entities: *ref_markers
        theme_mode: light

      - type: map
        entities: *ref_markers
        theme_mode: dark

      - type: map
        entities: *ref_markers
        theme_mode: auto