Bugfix/2938 add helm value access mode

[cmhdave]

Description

Adds a configuration option to the Helm chart to allow accessMode override for the persistent volume.

Related issues

• Close Helm Chart does not allow configuration of alternateReportStorage accessMode #2938

Remove this section if you don't have related PRs.

Checklist

• I've read the guidelines for contributing to this repository.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[CLAassistant]

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