fix(calendar) move the repeated code to the base file

Author: desig9stein

src/components/calendar/themes/calendar.base.scss

@@ -106,6 +106,8 @@
     flex-direction: row;
 
     [part='header'] {
+        width: rem(168px);
+        min-width: rem(168px);
         justify-content: flex-start;
         border-radius: inherit;
         border-start-end-radius: 0;

src/components/calendar/themes/shared/bootstrap/calendar.bootstrap.scss

@@ -51,13 +51,6 @@ $theme: $bootstrap;
     }
 }
 
-:host(igc-calendar[header-orientation='vertical']) {
-    [part~='header'] {
-        width: rem(168px);
-        min-width: rem(168px);
-    }
-}
-
 [part~='header'] {
     background: var-get($theme, 'header-background');
     color: var-get($theme, 'header-foreground');

src/components/calendar/themes/shared/fluent/calendar.fluent.scss

@@ -36,13 +36,6 @@ $theme: $fluent;
     }
 }
 
-:host(igc-calendar[header-orientation='vertical']) {
-    [part~='header'] {
-        width: rem(168px);
-        min-width: rem(168px);
-    }
-}
-
 [part='header'] {
     color: var-get($theme, 'header-foreground');
     background: var-get($theme, 'header-background');

src/components/calendar/themes/shared/material/calendar.material.scss

@@ -45,13 +45,6 @@ $theme: $material;
     width: 100%;
 }
 
-:host(igc-calendar[header-orientation='vertical']) {
-    [part~='header'] {
-        width: rem(168px);
-        min-width: rem(168px);
-    }
-}
-
 [part='header'] {
     padding: rem(16px) rem(24px);
     gap: rem(28px);