Firefox installation failing in aws/codebuild/standard:5.0 due to compression format change

Description
When building the aws/codebuild/standard:5.0 image, I encountered a build failure during the Firefox installation step. The issue stems from a change in Firefox's compression format: the downloadable file is now in .xz format rather than .bz2 as expected in the current Dockerfile.
Current Behavior
The build process downloads Firefox and attempts to extract it using bz2 decompression, which fails because the file is actually in xz format.
Steps to Reproduce

Attempt to build the aws/codebuild/standard:5.0 image
Observe the failure during Firefox extraction

Proposed Solution
The Dockerfile needs to be updated to account for the new compression format:

From:

```
dockerfileCopyRUN set -ex \
&& curl -L "https://download.mozilla.org/?product=firefox-latest&os=linux64" --output /tmp/FirefoxSetup.tar.bz2 \
&& tar xjf /tmp/FirefoxSetup.tar.bz2 -C /opt/ \
&& ln -s /opt/firefox/firefox /usr/local/bin/firefox \
&& rm -rf /tmp/* \
&& firefox --version
```

To:

```
dockerfileCopyRUN set -ex \
&& curl -L "https://download.mozilla.org/?product=firefox-latest&os=linux64" --output /tmp/FirefoxSetup.tar.xz \
&& tar xvf /tmp/FirefoxSetup.tar.xz -C /opt/ \
&& ln -s /opt/firefox/firefox /usr/local/bin/firefox \
&& rm -rf /tmp/* \
&& firefox --version
```

The changes involve:

Updating the output filename extension from .tar.bz2 to .tar.xz
Replacing the xjf flag (for bz2 extraction) with xvf (which will auto-detect the compression)

Thank you for your attention to this matter.

Locate the Dockerfile for the aws/codebuild/standard:5.0 image and start at its Firefox installation step. Build that image to reproduce the extraction failure, then verify the Firefox download extracts successfully and that the final firefox --version check passes.

Written by the indexing model from the issue text.