Remove terminal.html webpack entry point and notebooks terminal code

- Delete src/Terminal/ directory (JupyterLabAppFactory, index.ts/html/css, TerminalProps)
- Delete NotebookTerminalComponentAdapter (no longer needed)
- Simplify TerminalTab to always use CloudShellTerminalComponentAdapter
- Inline TerminalProps interface into NotebookTerminalComponent
- Remove src/Terminal/**/* from tsconfig.strict.json

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

webpack.config.js

@@ -111,7 +111,6 @@ module.exports = function (_env = {}, argv = {}) {
     index: "./src/Index.tsx",
     quickstart: "./src/quickstart.ts",
     hostedExplorer: "./src/HostedExplorer.tsx",
-    terminal: "./src/Terminal/index.ts",
     cellOutputViewer: "./src/CellOutputViewer/CellOutputViewer.tsx",
     selfServe: "./src/SelfServe/SelfServe.tsx",
     connectToGitHub: "./src/GitHub/GitHubConnector.ts",
@@ -128,11 +127,6 @@ module.exports = function (_env = {}, argv = {}) {
       template: "src/explorer.html",
       chunks: ["main"],
     }),
-    new HtmlWebpackPlugin({
-      filename: "terminal.html",
-      template: "src/Terminal/index.html",
-      chunks: ["terminal"],
-    }),
     new HtmlWebpackPlugin({
       filename: "quickstart.html",
       template: "src/quickstart.html",