Desired Outcome

Addresses #2438.

When changing a role's password, a check was recently added so that the operation would be refused for host roles.
This check breaks when changing the password for user:admin, resulting in the following server error:

RuntimeError (Resource not found for dev:user:admin)
app/models/role.rb:126:in `resource'
app/controllers/credentials_controller.rb:41:in `update_password'
app/controllers/application_controller.rb:79:in `run_with_transaction'

Implemented Changes

• Added a cucumber test case to confirm the password change failure for user admin

• Updated the host check:

  - raise Exceptions::Forbidden if @role.resource.kind == "host"
  + raise Exceptions::Forbidden if @role.login.start_with?("host/")

Connected Issue/Story

Resolves #2438

Definition of Done

At least 1 todo must be completed in the sections below for the PR to be
merged.

Changelog

• The CHANGELOG has been updated, or
• This PR does not include user-facing changes and doesn't require a
  CHANGELOG update

Test coverage

• This PR includes new unit and integration tests to go with the code
  changes, or
• The changes in this PR do not require tests

Documentation

• Docs (e.g. READMEs) were updated in this PR
• A follow-up issue to update official docs has been filed here: insert issue ID
• This PR does not require updating any documentation

Behavior

• This PR changes product behavior and has been reviewed by a PO, or
• These changes are part of a larger initiative that will be reviewed later, or
• No behavior was changed with this PR

Security

• Security architect has reviewed the changes in this PR,
• These changes are part of a larger initiative with a separate security review, or
• There are no security aspects to these changes