Check conda-forge channel first when installing conda packages. (#10035)

extensions/notebook/src/jupyter/jupyterServerInstallation.ts

@@ -625,7 +625,7 @@ export class JupyterServerInstallation implements IJupyterServerInstallation {
 		let versionSpecifier = useMinVersion ? '>=' : '==';
 		let packagesStr = packages.map(pkg => `"${pkg.name}${versionSpecifier}${pkg.version}"`).join(' ');
 		let condaExe = this.getCondaExePath();
-		let cmd = `"${condaExe}" install -y ${packagesStr}`;
+		let cmd = `"${condaExe}" install -c conda-forge -y ${packagesStr}`;
 		return this.executeStreamedCommand(cmd);
 	}