Fixes #29978 - Fix for uninitialized constant Host::JobInvocation

[stejskalleos]

Issue Skipping engine hook (uninitialized constant Host::JobInvocation) during plugin initialization.

How to reproduce the issue

• Add binding.pry before Host::JobInvocation.include ForemanLeapp::JobInvocationExtensions
• In pry:

  
  [1] pry(#<#<Class:0x000000000a5940c0>>)> Host::JobInvocation
  => JobInvocation(id: integer, targeting_id: integer, job_category: string, task_id: uuid, task_group_id: integer, triggering_id: integer, description: string, concurrency_level: integer, time_span: integer, execution_timeout_interval: integer, password: string, key_passphrase: string, remote_execution_feature_id: integer, sudo_password: string)

[2] pry(#<#>)> Host::JobInvocation NameError: uninitialized constant Host::JobInvocation from /home/lstejskal/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/active_support.rb:61:in `block in load_missing_constant' [3] pry(#<#>)>

**Fix**
Hook only `JobInvocation` instead of `Host::JobInvocation`