src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/AbstractInstallAction/computeAndUpdateEnablement
class AbstractInstallAction:	protected async computeAndUpdateEnablement(): Promise<void> {
		this.enabled = false;
		if (this.extension && !this.extension.isBuiltin) {
			if (this.extension.state === ExtensionState.Uninstalled && await this.extensionsWorkbenchService.canInstall(this.extension)) {
				this.enabled = this.installPreReleaseVersion ? this.extension.hasPreReleaseVersion : this.extension.hasReleaseVersion;
				this.updateLabel();
			}
		}
	}