3. Rename Sass mixins in src/material/legacy-dialog

Perform the following steps to complete the rename and fix all references:
1. Global find & replace `@include mat.dialog` with `@include mat.legacy-dialog`
2. In `src/material/legacy-dialog/_dialog-legacy-index.scss` and `src/material/legacy-dialog/_dialog-theme.import.scss`, find & replace `mat-dialog` with `mat-legacy-dialog`
3. In `src/material/_index.scss`, find the line that says `@forward './legacy-dialog/dialog-theme' as`. Change every instance of `dialog` after the word `as` to `legacy-dialog`
4. Run `yarn format`

Author: mmalerba

src/material/_index.scss

@@ -88,7 +88,7 @@
 @forward './chips/chips-theme' as chips-* show chips-theme, chips-color, chips-typography;
 @forward './datepicker/datepicker-theme' as datepicker-* show datepicker-theme, datepicker-color,
   datepicker-typography, datepicker-date-range-colors;
-@forward './legacy-dialog/dialog-theme' as dialog-* show dialog-theme, dialog-color, dialog-typography;
+@forward './legacy-dialog/dialog-theme' as legacy-dialog-* show legacy-dialog-theme, legacy-dialog-color, legacy-dialog-typography;
 @forward './divider/divider-theme' as divider-* show divider-theme, divider-color,
   divider-typography;
 @forward './expansion/expansion-theme' as expansion-* show expansion-theme, expansion-color,

src/material/legacy-dialog/_dialog-legacy-index.scss

@@ -1,2 +1,2 @@
 @forward 'dialog-theme' hide color, theme, typography;
-@forward 'dialog-theme' as mat-dialog-* hide mat-dialog-density;
+@forward 'dialog-theme' as mat-legacy-dialog-* hide mat-legacy-dialog-density;

src/material/legacy-dialog/_dialog-theme.import.scss

@@ -2,7 +2,7 @@
 @forward '../core/theming/theming.import';
 @forward '../core/typography/typography-utils.import';
 @forward 'dialog-theme' hide color, theme, typography;
-@forward 'dialog-theme' as mat-dialog-* hide mat-dialog-density;
+@forward 'dialog-theme' as mat-legacy-dialog-* hide mat-legacy-dialog-density;
 
 @import '../core/style/private';
 @import '../core/theming/palette';

src/material/schematics/ng-generate/mdc-migration/rules/components/dialog/dialog-styles.spec.ts

@@ -23,7 +23,7 @@ describe('dialog styles', () => {
         `
         @use '@angular/material' as mat;
         $theme: ();
-        @include mat.dialog-theme($theme);
+        @include mat.legacy-dialog-theme($theme);
       `,
         `
         @use '@angular/material' as mat;
@@ -56,8 +56,8 @@ describe('dialog styles', () => {
         @use '@angular/material' as mat;
         $light-theme: ();
         $dark-theme: ();
-        @include mat.dialog-theme($light-theme);
-        @include mat.dialog-theme($dark-theme);
+        @include mat.legacy-dialog-theme($light-theme);
+        @include mat.legacy-dialog-theme($dark-theme);
       `,
         `
         @use '@angular/material' as mat;
@@ -78,7 +78,7 @@ describe('dialog styles', () => {
         $theme: ();
 
 
-        @include mat.dialog-theme($theme);
+        @include mat.legacy-dialog-theme($theme);
 
 
       `,