fix: make sure Playwright works in DevContainers

This patch fixes Invalid browser name exception when Playwright is used in a DevContainer context

Fixes [#3174](https://github.com/CurlyFire/playwright-dotnet/issues/3174)

Author: CurlyFire

src/Playwright.TestAdapter/PlaywrightSettingsProvider.cs

@@ -41,7 +41,7 @@ public static string BrowserName
         {
             var browserFromEnv = Environment.GetEnvironmentVariable("BROWSER")?.ToLowerInvariant();
             // GitHub Codespaces and DevContainers sets the BROWSER environment variable, ignore it if its bogus.
-            if (!string.IsNullOrEmpty(browserFromEnv) && browserFromEnv!.StartsWith("/vscode/"))
+            if (!string.IsNullOrEmpty(browserFromEnv) && !browserFromEnv!.StartsWith("/vscode/"))
             {
                 ValidateBrowserName(browserFromEnv!, "'BROWSER' environment variable", "\nTry to remove 'BROWSER' environment variable for using default browser");
                 return browserFromEnv!;