chore(src/types): define "IThemeProps" interface as "DefaultTheme" object

src/types/styled-components.d.ts

@@ -0,0 +1,9 @@
+import "styled-components"
+import { IThemeProps } from "../lib/useTheme"
+
+// As of styled-components v6.1.17, we need to map our custom theme interface to the
+// default styled-components theme, as the type definition has been tightened with the merge request.
+// https://github.com/styled-components/styled-components/pull/4317
+declare module "styled-components" {
+    export interface DefaultTheme extends IThemeProps {}
+}