chore(material-ui): Don't use top level material-ui imports

This changes the @material-ui imports to not use top level imports
in packages/ as per eslint-rules enforced elsewhere.

Signed-off-by: Łukasz Jernaś <lukasz.jernas@allegro.com>

packages/theme/report.api.md

@@ -12,9 +12,10 @@ import { ReactNode } from 'react';
 import { Theme } from '@mui/material/styles';
 import { Theme as Theme_2 } from '@material-ui/core/styles';
 import { Theme as Theme_3 } from '@material-ui/core';
+import type { Theme as Theme_4 } from '@material-ui/core/styles/createTheme';
 import { ThemeOptions } from '@mui/material/styles';
 import { ThemeOptions as ThemeOptions_2 } from '@material-ui/core/styles';
-import type { ThemeOptions as ThemeOptions_3 } from '@material-ui/core';
+import type { ThemeOptions as ThemeOptions_3 } from '@material-ui/core/styles/createTheme';
 import { UnifiedTheme as UnifiedTheme_2 } from '@backstage/theme';
 
 // @public @deprecated
@@ -91,7 +92,7 @@ export type BackstagePaletteOptions = PaletteOptions &
   BackstagePaletteAdditions;
 
 // @public @deprecated
-export interface BackstageTheme extends Theme_3 {
+export interface BackstageTheme extends Theme_4 {
   // (undocumented)
   getPageTheme: (selector: PageThemeSelector) => PageTheme;
   // (undocumented)
@@ -188,13 +189,13 @@ export function createBaseThemeOptions<PaletteOptions>(
 };
 
 // @public @deprecated
-export function createTheme(options: SimpleThemeOptions): Theme_3;
+export function createTheme(options: SimpleThemeOptions): Theme_4;
 
 // @public @deprecated
 export function createThemeOptions(options: SimpleThemeOptions): ThemeOptions_3;
 
 // @public @deprecated
-export function createThemeOverrides(theme: Theme_3): Overrides;
+export function createThemeOverrides(theme: Theme_4): Overrides;
 
 // @public
 export function createUnifiedTheme(options: UnifiedThemeOptions): UnifiedTheme;

packages/theme/src/unified/UnifiedThemeProvider.tsx

@@ -15,7 +15,7 @@
  */
 
 import React, { ReactNode } from 'react';
-import { CssBaseline } from '@material-ui/core';
+import CssBaseline from '@material-ui/core/CssBaseline';
 import {
   ThemeProvider,
   StylesProvider,

packages/theme/src/v4/baseTheme.ts

@@ -16,12 +16,10 @@
 
 import { Theme as Mui5Theme } from '@mui/material/styles';
 import { createTheme as createMuiTheme } from '@material-ui/core/styles';
-import type {
-  GridProps,
-  SwitchProps,
-  Theme,
-  ThemeOptions,
-} from '@material-ui/core';
+import type { Theme, ThemeOptions } from '@material-ui/core/styles/createTheme';
+import type { GridProps } from '@material-ui/core/Grid';
+import type { SwitchProps } from '@material-ui/core/Switch';
+
 import { Overrides } from '@material-ui/core/styles/overrides';
 import { SimpleThemeOptions } from './types';
 import { createBaseThemeOptions } from '../base';

packages/theme/src/v4/types.ts

@@ -17,7 +17,7 @@
 import type {
   Theme as MuiTheme,
   ThemeOptions as MuiThemeOptions,
-} from '@material-ui/core';
+} from '@material-ui/core/styles/createTheme';
 import type {
   PaletteOptions as MuiPaletteOptions,
   Palette as MuiPalette,