stream_color: Remove spectrum-colorpicker library.

As a follow-up to the previous commit which replaces the spectrum color
picker instances with the custom color picker popover, this commit
removes the spectrum-colorpicker library and its related code from the
codebase.

package.json

@@ -75,7 +75,6 @@
     "sorttable": "^1.0.2",
     "source-code-pro": "^2.38.0",
     "source-sans": "^3.28.0",
-    "spectrum-colorpicker": "^1.8.1",
     "stackframe": "^1.3.4",
     "stacktrace-gps": "^3.0.4",
     "style-loader": "^4.0.0",
@@ -118,7 +117,6 @@
     "@types/node": "^22.9.0",
     "@types/plotly.js": "^2.12.20",
     "@types/sortablejs": "^1.15.1",
-    "@types/spectrum": "^1.8.4",
     "@types/textarea-caret": "^3.0.3",
     "@types/throttle-debounce": "^5.0.2",
     "@types/tinycolor2": "^1.4.5",