feat(@schematics/angular): remove ngOnInit from component template

This commit removes the `constructor` and `ngOnInit` as most of the users prefer to add this manually if needed.

Closes #23678

packages/schematics/angular/component/files/__name@dasherize@if-flat__/__name@dasherize__.__type@dasherize__.ts.template

@@ -1,4 +1,4 @@
-import { <% if(changeDetection !== 'Default') { %>ChangeDetectionStrategy, <% }%>Component, OnInit<% if(!!viewEncapsulation) { %>, ViewEncapsulation<% }%> } from '@angular/core';<% if(standalone) {%>
+import { <% if(changeDetection !== 'Default') { %>ChangeDetectionStrategy, <% }%>Component<% if(!!viewEncapsulation) { %>, ViewEncapsulation<% }%> } from '@angular/core';<% if(standalone) {%>
 import { CommonModule } from '@angular/common';<% } %>
 
 @Component({<% if(!skipSelector) {%>
@@ -22,11 +22,6 @@ import { CommonModule } from '@angular/common';<% } %>
   encapsulation: ViewEncapsulation.<%= viewEncapsulation %><% } if (changeDetection !== 'Default') { %>,
   changeDetection: ChangeDetectionStrategy.<%= changeDetection %><% } %>
 })
-export class <%= classify(name) %><%= classify(type) %> implements OnInit {
-
-  constructor() { }
-
-  ngOnInit(): void {
-  }
+export class <%= classify(name) %><%= classify(type) %> {
 
 }

packages/schematics/angular/component/index_spec.ts

@@ -297,7 +297,7 @@ describe('Component Schematic', () => {
     const tree = await schematicRunner.runSchematicAsync('component', options, appTree).toPromise();
     const content = tree.readContent('/projects/bar/src/app/foo/foo.route.ts');
     const testContent = tree.readContent('/projects/bar/src/app/foo/foo.route.spec.ts');
-    expect(content).toContain('export class FooRoute implements OnInit');
+    expect(content).toContain('export class FooRoute');
     expect(testContent).toContain("describe('FooRoute'");
     expect(tree.files).toContain('/projects/bar/src/app/foo/foo.route.css');
     expect(tree.files).toContain('/projects/bar/src/app/foo/foo.route.html');
@@ -308,7 +308,7 @@ describe('Component Schematic', () => {
     const tree = await schematicRunner.runSchematicAsync('component', options, appTree).toPromise();
     const content = tree.readContent('/projects/bar/src/app/foo/foo.ts');
     const testContent = tree.readContent('/projects/bar/src/app/foo/foo.spec.ts');
-    expect(content).toContain('export class Foo implements OnInit');
+    expect(content).toContain('export class Foo');
     expect(testContent).toContain("describe('Foo'");
     expect(tree.files).toContain('/projects/bar/src/app/foo/foo.css');
     expect(tree.files).toContain('/projects/bar/src/app/foo/foo.html');