bug: Unable to set theme color for strokeStyle.color in 'relations'

[MinCrohn]

Describe the bug

A problem occurs when specifying the color value for the strokeStyle property of type relations.
An error occurs if a color assignment such as primary.default is performed, similar to how colors are changed for other components.

[
  {
    "type": "relations",
    "id": "relations-uid-1",
    "links": [
      { "source": "array-uid-1.0.0", "target": "array-uid-1.1.0" },
      { "source": "array-uid-1.1.0", "target": "array-uid-1.1.1" }
    ],
    "strokeStyle": {
      "width": 4,
      "color": "primary.default",
      "cap": "round",
      "join": "round"
    }
  }
]

Reproduction

1. add relations type.
2. set the strokeStyle's color value to primary.default.

Environment

System:
  OS: macOS 14.0
  CPU: (8) arm64 Apple M2
  Memory: 81.38 MB / 16.00 GB
  Shell: 5.9 - /bin/zsh
Binaries:
  Node: 20.18.2 - ~/.nvm/versions/node/v20.18.2/bin/node
  npm: 11.1.0 - ~/.nvm/versions/node/v20.18.2/bin/npm
  bun: 1.1.45 - /opt/homebrew/bin/bun
Browsers:
  Chrome: 136.0.7103.116
  Safari: 17.0