fix(button): revert primary button content color (#3550)

Bug fix: Revert primary button content color to spectrum-white to bring back white color in both dark and light themes.

Author: rise-erpelding

.changeset/metal-bees-bake.md

@@ -0,0 +1,5 @@
+---
+"@spectrum-css/button": patch
+---
+
+Revert primary button content color to spectrum-white to bring back white color in both dark and light themes.

components/button/themes/spectrum.css

@@ -23,10 +23,10 @@
 		--mod-button-background-color-focus: var(--spectrum-gray-200);
 
 		&.spectrum-Button--primary {
-			--mod-button-content-color-default: var(--spectrum-gray-50);
-			--mod-button-content-color-hover: var(--spectrum-gray-50);
-			--mod-button-content-color-down: var(--spectrum-gray-50);
-			--mod-button-content-color-focus: var(--spectrum-gray-50);
+			--mod-button-content-color-default: var(--spectrum-white);
+			--mod-button-content-color-hover: var(--spectrum-white);
+			--mod-button-content-color-down: var(--spectrum-white);
+			--mod-button-content-color-focus: var(--spectrum-white);
 
 			&.spectrum-Button--outline {
 				--mod-button-background-color-hover: var(--spectrum-gray-300);