Fix docker build

Lack of `fi` resulted in a syntax error.
Also, change `;` to `||` to ensure it builds successfully on architectures other than `linux/arm/v7`.


```
[2023-10-24T10:46:49.941Z] ------
 > [dev_container_auto_added_stage_label 11/18] RUN mkdir -p "/home/archivebox/.config/chromium/Crash Reports/pending/"     && chown -R archivebox "/home/archivebox/.config"     ; if [[ "linux/amd64" == "linux/arm/v7" ]]; then $exit 0; else exit 1:
0.401 /bin/bash: -c: line 2: syntax error: unexpected end of file
------
WARNING: buildx: git was not found in the system. Current commit information was not captured by the build
[2023-10-24T10:46:49.942Z] Dockerfile-with-features:135
--------------------
 134 |         && ln -s "$CHROME_BINARY" /usr/bin/chromium-browser
 135 | >>> RUN mkdir -p "/home/${ARCHIVEBOX_USER}/.config/chromium/Crash Reports/pending/" \
 136 | >>>     && chown -R $ARCHIVEBOX_USER "/home/${ARCHIVEBOX_USER}/.config" \
 137 | >>>     ; if [[ "$TARGETPLATFORM" == "linux/arm/v7" ]]; then $exit 0; else exit 1
 138 |         # ignore failure for architectures where no playwright release is available yet
--------------------
ERROR: failed to solve: process "/bin/bash -c mkdir -p \"/home/${ARCHIVEBOX_USER}/.config/chromium/Crash Reports/pending/\"     && chown -R $ARCHIVEBOX_USER \"/home/${ARCHIVEBOX_USER}/.config\"     ; if [[ \"$TARGETPLATFORM\" == \"linux/arm/v7\" ]]; then $exit 0; else exit 1" did not complete successfully: exit code: 2
```

Dockerfile

@@ -122,7 +122,7 @@ RUN echo "[+] Installing extractor Chromium dependency..." \
     && ln -s "$CHROME_BINARY" /usr/bin/chromium-browser \
     && mkdir -p "/home/${ARCHIVEBOX_USER}/.config/chromium/Crash Reports/pending/" \
     && chown -R $ARCHIVEBOX_USER "/home/${ARCHIVEBOX_USER}/.config" \
-    ; if [[ "$TARGETPLATFORM" == "linux/arm/v7" ]]; then $exit 0; else exit 1
+    || if [[ "$TARGETPLATFORM" == "linux/arm/v7" ]]; then exit 0; else exit 1; fi
     # ignore failure for architectures where no playwright release is available yet
 
 # Install Node dependencies