Remove gallery.html and all associated gallery functionality (#2474)

* Remove gallery.html and all associated gallery functionality

Remove the standalone gallery.html entry point, the in-app gallery tab,
the publish-to-gallery pane, and all gallery-related components, utilities,
and API methods that are no longer needed.

Deleted:
- src/GalleryViewer/ (standalone entry point)
- src/Explorer/Controls/NotebookGallery/ (gallery components)
- src/Explorer/Controls/Header/GalleryHeaderComponent.tsx
- src/Explorer/Tabs/GalleryTab.tsx
- src/Explorer/Panes/PublishNotebookPane/ (publish pane)
- src/Utils/GalleryUtils.ts and tests
- images/GalleryIcon.svg

Edited:
- webpack.config.js (removed entry point and HTML plugin)
- Explorer.tsx (removed openGallery, publishNotebook methods)
- ResourceTreeAdapter.tsx (removed gallery tree node and publish menu)
- NotebookV2Tab.ts (removed publish-to-gallery button)
- NotebookManager.tsx (removed openPublishNotebookPane)
- NotebookViewerComponent.tsx (stripped gallery actions)
- JunoClient.ts (removed gallery interfaces and API methods)
- TelemetryConstants.ts, Constants.ts, ViewModels.ts,
  extractFeatures.ts, useKnockoutExplorer.ts (removed gallery constants)

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

* Update package-lock

* Revert changes to Telemetry Constants

---------

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

src/Explorer/Notebook/NotebookManager.tsx

@@ -17,16 +17,13 @@ import { JunoClient } from "../../Juno/JunoClient";
 import { Action, ActionModifiers } from "../../Shared/Telemetry/TelemetryConstants";
 import * as TelemetryProcessor from "../../Shared/Telemetry/TelemetryProcessor";
 import { userContext } from "../../UserContext";
-import { getFullName } from "../../Utils/UserUtils";
 import { useDialog } from "../Controls/Dialog";
 import Explorer from "../Explorer";
 import { CopyNotebookPane } from "../Panes/CopyNotebookPane/CopyNotebookPane";
 import { GitHubReposPanel } from "../Panes/GitHubReposPanel/GitHubReposPanel";
-import { PublishNotebookPane } from "../Panes/PublishNotebookPane/PublishNotebookPane";
 import { ResourceTreeAdapter } from "../Tree/ResourceTreeAdapter";
 import { InMemoryContentProvider } from "./NotebookComponent/ContentProviders/InMemoryContentProvider";
 import { NotebookContentProvider } from "./NotebookComponent/NotebookContentProvider";
-import { SnapshotRequest } from "./NotebookComponent/types";
 import { NotebookContainerClient } from "./NotebookContainerClient";
 import { NotebookContentClient } from "./NotebookContentClient";
 import { SchemaAnalyzerNotebook } from "./SchemaAnalyzer/SchemaAnalyzerUtils";
@@ -124,31 +121,6 @@ export default class NotebookManager {
     }
   }
 
-  public async openPublishNotebookPane(
-    name: string,
-    content: NotebookPaneContent,
-    notebookContentRef: string,
-    onTakeSnapshot: (request: SnapshotRequest) => void,
-    onClosePanel: () => void,
-  ): Promise<void> {
-    useSidePanel
-      .getState()
-      .openSidePanel(
-        "Publish Notebook",
-        <PublishNotebookPane
-          explorer={this.params.container}
-          junoClient={this.junoClient}
-          name={name}
-          author={getFullName()}
-          notebookContent={content}
-          notebookContentRef={notebookContentRef}
-          onTakeSnapshot={onTakeSnapshot}
-        />,
-        "440px",
-        onClosePanel,
-      );
-  }
-
   public openCopyNotebookPane(name: string, content: string): void {
     const { container } = this.params;
     useSidePanel