Improved Organization detection

[dadgar]

Changes proposed in this PR:

Previously, the organization was only auto-detected if both the organization and project ID were unset. Now if the organization is not set, it will be detected regardless of the project ID.

How I've tested this PR:

# Create a project SP and configure the cli to use it by setting the env vars
$ hcp iam sp keys create <sp-name>
$ export HCP_CLIENT_ID="..."
$ export HCP_CLIENT_SECRET="..."

# Override my active profile to have a bogus project ID and no org ID
$ printf 'name = "test"\norganization_id = ""\nproject_id = "2CDCE738-DB42-4FD4-8418-FDCF3A29B066"\n' > ~/.config/hcp/profiles/test.hcl
$ cat ~/.config/hcp/profiles/test.hcl && hcp profile display
name = "test"
organization_id = ""
project_id = "2CDCE738-DB42-4FD4-8418-FDCF3A29B066"

# Display the profile. This will run the detection logic because the organization ID isn't set.
# We can see it detected and set the org id but didn't touch the project ID as desired.
$ hcp profile display
name            = "test"
organization_id = "11ea8f23-1571-a43d-84e2-0242ac110007"
project_id      = "2CDCE738-DB42-4FD4-8418-FDCF3A29B066"

How I expect reviewers to test this PR:

Code review

Checklist:

• Tests added if applicable
• CHANGELOG entry added or label 'pr/no-changelog' added to PR

  Run CHANGELOG_PR=<PR number> make changelog/new-entry for guidance
  in authoring a changelog entry, and commit the resulting file, which should
  have a name matching your PR number. Entries should use imperative present
  tense (e.g. Add support for...)