Fix issues is kubectl-mongodb related assets in github

[viveksinghggits]

Summary

In the traditional way of releasing the kubectl plugin when we decompressed the tar, after downloading it from github releases, we directly go the binary and the .sig file. This binary file already had requires permissions to get executed.

But after our last changes to use promotion process to release the kubectl plugin, we unknowingly changed this a little in such a way that

1. When we decompressed the tar file we got a dir and that dir had the respective binary and .sig file
2. The binary file didn't have necessary permissions set to get executed.

Because above 2 changes are not required and we would not like to change the way users have been downloading and using the binary, we would like to make sure that they get the same experience. This PR does that. It makes sure that the binary has correct permissions and decompressing the .tar.gz directly gives us binary.

Proof of Work

https://spruce.mongodb.com/version/68fa1efb2a851e0007d34504/tasks?sorts=STATUS%3AASC%3BBASE_STATUS%3ADESC

Checklist

• Have you linked a jira ticket and/or is the ticket in the title?
• Have you checked whether your jira ticket required DOCSP changes?
• Have you added changelog file?
  • use skip-changelog label if not needed
  • refer to Changelog files and Release Notes section in CONTRIBUTING.md for more details

[github-actions]

⚠️ (this preview might not be accurate if the PR is not rebased on current master branch)

MCK 1.6.0 Release Notes

New Features

• MongoDBCommunity: Added support to configure custom cluster domain via newly introduced spec.clusterDomain resource field. If spec.clusterDomain is not set, environment variable CLUSTER_DOMAIN is used as cluster domain. If the environment variable CLUSTER_DOMAIN is also not set, operator falls back to cluster.local as default cluster domain.
• Helm Chart: Introduced two new helm fields operator.podSecurityContext and operator.securityContext that can be used to configure securityContext for Operator deployment through Helm Chart.

Bug Fixes

• Fixed parsing of the customEnvVars Helm value when values contain = characters.

[MaciejKaras]

LGTM