fix:(button) fix color inconsistency in wc and angular bootstrap theme (#11272)

Author: desig9stein

projects/igniteui-angular/src/lib/core/styles/themes/schemas/light/_button.scss

@@ -539,6 +539,7 @@ $bootstrap-outlined-button: extend(
 /// @type {Map}
 /// @prop {Color} hover-foreground [contrast-color: ('primary', 600)] - The hover text color of an raised button.
 /// @prop {Color} focus-foreground [contrast-color: ('primary', 600)] - The focus text color of an raised button.
+/// @prop {Map} foreground [contrast-color: ('primary', 600)] - The idle text color of an outlined button.
 /// @prop {Map} background [color: ('primary', 500)] - The background color of a raised button.
 /// @prop {Map} hover-background [color: ('primary', 600)] - The hover background color of an raised button.
 /// @prop {Map} focus-background [color: ('primary', 600)] - The focus background color of an raised button.
@@ -561,6 +562,10 @@ $bootstrap-raised-button: extend(
             contrast-color: ('primary', 600)
         ),
 
+        foreground: (
+            contrast-color: ('primary', 600)
+        ),
+
         background: (
             color: ('primary', 500)
         ),