feat(secret): add support for WriteOnly data argument in secret version

[estellesoulard]

Context

I was implementing key manager's Encrypt call as an Ephemeral Resource. This kind of resource seems like the most appropriate implementation choice (Ephemeral Resources are not persisted in state, and seems perfect for the use case of returning an encrypted payload).
To test this Ephemeral Resource, I needed a matching resource argument that I could transfer my Ephemeral Resource's value into. This is necessary because Ephemeral Resources cannot be outputted nor used liberally in any other resource, therefore in the acceptance tests I had no way to check that the Ephemeral Resource properly worked.
However, an Ephemeral Resource's attribute value can be transferred into a WriteOnly argument, that I could later retrieve in the target resource's datasource. This is exactly what I did here 😄

PR content: TLDR

This PR adds a data_wo argument to secret_version Resource that can be used alternatively to the classic data argument.
Since this data_wo is a WriteOnly it is not stored in the state, and drifts cannot be detected. It is fundamentally incompatible with ForceNew. I bypassed this issue by adding a data_wo_version with ForceNew, enabling a simili-ForceNew for data_wo: updating data_wo requires to update data_wo_version, which will then be properly caught by Terraform and trigger a recreation.

A word of caution

This PR is the first in a long line of WriteOnly attribute additions. (cf #3423). It may be treated as a blueprint for the following ones: please raise any concern during your review 🫡

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 1.70%. Comparing base (6900a12) to head (61ef696).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
internal/services/secret/version.go	0.00%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #3538      +/-   ##
=========================================
- Coverage    1.71%   1.70%   -0.01%     
=========================================
  Files         434     434              
  Lines       47517   47527      +10     
=========================================
- Hits          813     811       -2     
- Misses      46616   46627      +11     
- Partials       88      89       +1     

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