feat: return team members and slack channels in team data source

[c4po]

Summary

This pull request enhances the Terraform Cortex provider by improving the team data source to return both team members and Slack channels.
It also addresses a compatibility issue with the Terraform Plugin Framework by ensuring all struct fields used for schema mapping have the required tfsdk struct tags.

Changes

• Feature:
  • The team data source now returns detailed information about team members and Slack channels, making it easier for users to access and utilize this data in their Terraform configurations.
• Bugfix / Compatibility:
  • Added tfsdk struct tags to the TeamSlackChannel struct fields in internal/cortex/teams.go to resolve errors related to missing struct tags required by the Terraform Plugin Framework.

Motivation

#52

Testing

Verified that the team data source now returns both team members and Slack channels as expected.

provider "cortex" {
  token = "..."
}

data "cortex_team" "team" {
  tag = "..."
}

output "team" {
  value = data.cortex_team.squad
}

Changes to Outputs:
  + team = {
      + id             = "..."
      + members        = [
          + {
              + description = "..."
              + email       = "..."
              + name        = "..."
            },
...
        ]
      + slack_channels = [
          + {
              + name                  = "..."
              + notifications_enabled = true
            },
          + {
              + name                  = "..."
              + notifications_enabled = false
            },
        ]
      + tag            = "..."
    }

[stpierre]

Couple of small things. Please be sure to add tests as appropriate.

[stpierre]

Are these if blocks strictly necessary? At a glance it looks like this would be equivalent to:

data.Members = teamResponse.CortexTeam.Members
data.SlackChannels = teamResponse.SlackChannels