[BUG] `no-unnecessary-arbitrary-value` does not support color object syntax

[Grapedge]

Describe the bug
When using the color-object-syntax, this plugin fails to correctly detect unnecessary arbitrary values.

To Reproduce

var config = [
  {
    config: {
      theme: {
        colors: {
          blue: {
            50: "#abcdef",
          },
          "blue-100": "#123456",
        },
      },
    },
  },
];

ruleTester.run("arbitrary-values", rule, {
  valid: [],
  invalid: [
    {
      // AssertionError [ERR_ASSERTION]: Should have 1 error but had 0: []
      code: `<pre class="text-[#abcdef]">text-[#abcdef]</pre>`,
      options: config,
      output: `<pre class="text-blue-50">text-[#abcdef]</pre>`,
      errors: generateErrors(["text-[#abcdef]"], [["text-blue-50"]]),
    },
    {
      // This works correctly
      code: `<pre class="text-[#123456]">text-[#123456]</pre>`,
      options: config,
      output: `<pre class="text-blue-100">text-[#123456]</pre>`,
      errors: generateErrors(["text-[#123456]"], [["text-blue-100"]]),
    },
  ],
});

Screenshots