Allow non-AMD64 devcontainer, such as ARM (reverts zauberzeug#3328) (zauberzeug#5206)

### Motivation

I just checked and we can install `chromium` and `chromium-driver` on
ARM64, covering a major use case of developing on Apple Silicon Macs

<img width="599" height="99" alt="image"
src="https://github.com/user-attachments/assets/b6fb8be5-5778-4225-a143-a6fe9fbc7350"
/>

I can't trace back which release it was supported, though. 

So we can revert zauberzeug#3328 and improve devcontainer performance. 

For those who need AMD64 they can specify it themselves? 

### Implementation

Revert zauberzeug#3328, drop `--platform=linux/amd64`

### Progress

- [x] I chose a meaningful title that completes the sentence: "If
applied, this PR will..."
- [x] The implementation is complete.
- [x] Pytests are not necessary.
- [x] Documentation is not necessary.

Author: evnchn

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM --platform=linux/amd64 python:3.9
+FROM python:3.9
 
 ENV POETRY_VERSION=2.1.2 \
     POETRY_NO_INTERACTION=1 \

nicegui/testing/screen_plugin.py

@@ -64,8 +64,15 @@ def nicegui_remove_all_screenshots() -> None:
 @pytest.fixture()
 def nicegui_driver(nicegui_chrome_options: webdriver.ChromeOptions) -> Generator[webdriver.Chrome, None, None]:
     """Create a new Chrome driver instance."""
-    s = Service()
-    driver_ = webdriver.Chrome(service=s, options=nicegui_chrome_options)
+    for executable_path in (None, shutil.which('chromedriver'), 'chromedriver'):  # Required for ARM devcontainers
+        try:
+            s = Service(executable_path=executable_path)
+            driver_ = webdriver.Chrome(service=s, options=nicegui_chrome_options)
+            break
+        except Exception:
+            continue
+    else:  # no break
+        raise RuntimeError('Could not start Chrome WebDriver.')
     driver_.implicitly_wait(Screen.IMPLICIT_WAIT)
     driver_.set_page_load_timeout(4)
     yield driver_