ethtool-test.py control characters issue and wrong link in official website

[anncheng-arm]

1. When switching to use the Python script, some control characters are redirected to ethtool_test.log, which causes parsing issues in the generated report.

2. The script link in this page needs to be updated: Test-installation-of-Linux-distributions.
   • Option A: Update the link to point to the correct script.
   • Option B: Remove the script link from the webpage and instead directly link to the GitHub README section.

The original issue:

### Description: 
When running ethtool-test.sh on a system where /bin/sh is not bash (e.g. Debian/Ubuntu, where /bin/sh is linked to dash), the script fails immediately with a syntax error:

./ethtool-test.sh: 30: Syntax error: "(" unexpected

This happens because the script uses Bash-specific features (arrays, [[ ]], =~, for (( )), etc.) but the shebang is #!/bin/sh. In POSIX sh, these constructs are not supported.

Update #!/bin/sh to be #!/bin/bash then issue is gone.

### Environment:
Debian 13

[chetan-rathore]

Hi @anncheng-arm,

Thanks for testing at your end. Please note the latest ethtool test script is python based. Please test using this and let us know if any command or dependency related error is seen on debian enviroment.

[anncheng-arm]

Hi @chetan-rathore ,

2 issues:

1. When switching to use the Python script, some control characters are redirected to ethtool_test.log, which causes parsing issues in the generated report.

2. The script link in this page needs to be updated: Test-installation-of-Linux-distributions.
   • Option A: Update the link to point to the correct script.
   • Option B: Remove the script link from the webpage and instead directly link to the GitHub README section.

[chetan-rathore]

thanks @anncheng-arm.

@Ashishsharma1903 please check on this.

[anncheng-arm]

Test result looks good in 3.1.0