Extract avatar URL check into utility function

Add DataUri.isGitHubDotComAvatar() utility to check if an avatar URL
is from GitHub.com. Use this utility in all tree view nodes instead of
inline .includes() checks.

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

src/common/uri.ts

@@ -290,6 +290,16 @@ export namespace DataUri {
 		return asImageDataURI(contents);
 	}
 
+	/**
+	 * Checks if an avatar URL is from GitHub.com (as opposed to GitHub Enterprise).
+	 * GitHub.com avatar URLs contain 'githubusercontent.com', while enterprise avatar URLs do not.
+	 * @param avatarUrl The avatar URL to check
+	 * @returns true if the avatar is from GitHub.com, false otherwise
+	 */
+	export function isGitHubDotComAvatar(avatarUrl: string | undefined): boolean {
+		return avatarUrl?.includes('githubusercontent.com') ?? false;
+	}
+
 	export async function avatarCirclesAsImageDataUris(context: vscode.ExtensionContext, users: (IAccount | ITeam)[], height: number, width: number, localOnly?: boolean): Promise<(vscode.Uri | undefined)[]> {
 		let cacheLogOrder: string[];
 		const cacheLog = cacheLogUri(context);

src/issues/issuesView.ts

@@ -102,7 +102,7 @@ export class IssuesTreeData
 
 		if (avatarUser) {
 			// For enterprise, use placeholder icon instead of trying to fetch avatar
-			if (!avatarUser.avatarUrl?.includes('githubusercontent.com')) {
+			if (!DataUri.isGitHubDotComAvatar(avatarUser.avatarUrl)) {
 				treeItem.iconPath = new vscode.ThemeIcon('github');
 			} else {
 				treeItem.iconPath = (await DataUri.avatarCirclesAsImageDataUris(this.context, [avatarUser], 16, 16))[0] ??

src/view/treeNodes/commitNode.ts

@@ -41,7 +41,7 @@ export class CommitNode extends TreeNode implements vscode.TreeItem {
 	async getTreeItem(): Promise<vscode.TreeItem> {
 		if (this.commit.author) {
 			// For enterprise, use placeholder icon instead of trying to fetch avatar
-			if (!this.commit.author.avatar_url?.includes('githubusercontent.com')) {
+			if (!DataUri.isGitHubDotComAvatar(this.commit.author.avatar_url)) {
 				this.iconPath = new vscode.ThemeIcon('github');
 			} else {
 				const author: IAccount = { id: this.commit.author.node_id, login: this.commit.author.login, url: this.commit.author.url, avatarUrl: this.commit.author.avatar_url, accountType: this.commit.author.type as AccountType };

src/view/treeNodes/pullRequestNode.ts

@@ -272,7 +272,7 @@ export class PRNode extends TreeNode implements vscode.CommentingRangeProvider2
 
 	private async _getAuthorIcon(): Promise<vscode.Uri | vscode.ThemeIcon> {
 		// For enterprise, use placeholder icon instead of trying to fetch avatar
-		if (!this.pullRequestModel.author.avatarUrl?.includes('githubusercontent.com')) {
+		if (!DataUri.isGitHubDotComAvatar(this.pullRequestModel.author.avatarUrl)) {
 			return new vscode.ThemeIcon('github');
 		}
 		return (await DataUri.avatarCirclesAsImageDataUris(this._folderReposManager.context, [this.pullRequestModel.author], 16, 16))[0]

src/view/treeNodes/repositoryChangesNode.ts

@@ -112,7 +112,7 @@ export class RepositoryChangesNode extends TreeNode implements vscode.TreeItem {
 	override async getTreeItem(): Promise<vscode.TreeItem> {
 		this.setLabel();
 		// For enterprise, use placeholder icon instead of trying to fetch avatar
-		if (!this.pullRequestModel.author.avatarUrl?.includes('githubusercontent.com')) {
+		if (!DataUri.isGitHubDotComAvatar(this.pullRequestModel.author.avatarUrl)) {
 			this.iconPath = new vscode.ThemeIcon('github');
 		} else {
 			this.iconPath = (await DataUri.avatarCirclesAsImageDataUris(this._pullRequestManager.context, [this.pullRequestModel.author], 16, 16))[0];