applications: nrf5340_audio: Expand SD card module

[mVaardal]

To avoid unnecessary opening
and closing of files

[CLAassistant]

All committers have signed the CLA.

[NordicBuilder]

Thank you for your contribution!
It seems you are not a member of the nrfconnect GitHub organization. External contributions are handled as follows:
Large contributions, affecting multiple subsystems for example, may be rejected if they are complex, may introduce regressions due to lack of test coverage, or if they are not consistent with the architecture of nRF Connect SDK.
PRs will be run in our continuous integration (CI) test system.
If CI passes, PRs will be tagged for review and merged on successful completion of review. You may be asked to make some modifications to your contribution during review.
If CI fails, PRs may be rejected or may be tagged for review and rework.
PRs that become outdated due to other changes in the repository may be rejected or rework requested.
External contributions will be prioritized for review based on the relevance to current development efforts in nRF Connect SDK. Bug fix PRs will be prioritized.
You may raise issues or ask for help from our Technical Support team by visiting https://devzone.nordicsemi.com/.

Note: This comment is automatically posted and updated by the Contribs GitHub Action.

[koffes]

This is the same code as in #11642

[NordicBuilder]

Test specification

CI/Jenkins/NRF

• Integration Platforms

CI/Jenkins/integration

Test Module	File based changes	Manually selected	West overwrite
test-sdk-audio	X

Detailed information of selected test modules

Note: This message is automatically posted and updated by the CI