fix(rust): ockam enroll command to not require custom attributes

[p-gentili]

Current Behavior

ockam project enroll command requires any arguments to work even though, for the enrollment token workflow, none are needed.

Proposed Changes

Removed rust attribute to enforce passing CLI attributes when invoking ockam project enroll.
Fixes #4135

Checks

• All commits in this Pull Request are signed and Verified by Github.
• All commits in this Pull Request follow the Ockam commit message convention.
• I accept the Ockam Community Code of Conduct.
• I have accepted the Ockam Contributor License Agreement by adding my Git/Github details in a row at the end of the CONTRIBUTORS.csv file in a separate pull request to the build-trust/ockam-contributors repository.

[mrinalwadhwa]

@p-gentili Thank you for an awesome first pull request, while I review and before we can merge please

• Accept the Ockam Contributor License Agreement by adding your Git/Github details in a row at the end of the CONTRIBUTORS.csv file in a separate pull request to the build-trust/ockam-contributors repository.

The easiest way to do this is to edit the CONTRIBUTORS.csv file in the github web UI and create a PR, this will make the commit as verified.

[p-gentili]

@p-gentili Thank you for an awesome first pull request, while I review and before we can merge please

* [ ]  Accept the Ockam [Contributor License Agreement](https://github.com/build-trust/ockam-contributors/blob/main/CLA.md) by adding your Git/Github details in a row at the end of the [CONTRIBUTORS.csv](https://github.com/build-trust/ockam-contributors/blob/main/CONTRIBUTORS.csv) file in a separate pull request to the [build-trust/ockam-contributors](https://github.com/build-trust/ockam-contributors) repository.

The easiest way to do this is to edit the CONTRIBUTORS.csv file in the github web UI and create a PR, this will make the commit as verified.

Sorry about that, I must have missed this needed to be explicit. https://github.com/build-trust/ockam-contributors/pull/183

[p-gentili]

@mrinalwadhwa I amended my commit with signature. Please re run the workflow.

[p-gentili]

@mrinalwadhwa now I can see my signature when running git log --show-signature.

[p-gentili]

@mrinalwadhwa it failed because the email associated with the key was not the one in the csv. Another try please (and thanks for your time...)

[mrinalwadhwa]

@p-gentili Thank you for fixing the errors and congratulations on an awesome first contribution 🥳