Update ad7746 test

[trishaange01]

Description

This change includes removing the tests checking for offset on differential capacitance and input on temperature, to remove the test failures. The issue is caused by the offset being defined on the differential channels and input being defined on temperature channels, which were seen on the iio_info when the test was made. The updated iio_info does not include these attributes on the channels mentioned and this is the correct behavior.
Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

How has this been tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• Hardware:
• OS:

Documentation

If this is a new feature or example please mention or link any documentation. All new hardware interface classes require documentation.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have signed off all commits and they contain "Signed-off by: "
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules