Adjust extra_vars handling in non-json cases

[JacobCallahan]

It seems that we don't always get a json object back from the api for the extra_vars available in a job. In these cases, we'll try a custom parser.

[JacobCallahan]

logs from an execute that this was initially encountered in.

[I 240319 10:05:33 ansible_tower:579] No inventory specified, Ansible Tower will use a default.
[W 240319 10:05:33 ansible_tower:429] Job uses non-json extra_vars: deploy_scenario: satellite-upgrade-source
    deploy_rhel_version: ''
    deploy_sat_version: ''
    deploy_snap_version: ''
    upgrade_path: ''
    snap_description: UMB created template by Jenkins Pipeline
    yum_install_packages_disable_gpg_check: 'yes'
    deploy_flavor: satqe-ssd.upgrade.std
    target_memory: 24GiB
    target_cores: '6'
    wait_timeout: '3600'
    deploy_timeout: '3600'
    osp_create_snapshot_convert_to_qcow: false
    osp_create_snapshot_virt_sysprep_operations: defaults,-puppet-data-log
    Attempting to parse as pseudo-dictionary.
[D 240319 10:05:33 ansible_tower:588] Launching workflow: ...

[tpapaioa]

Verified on a workflow job template that had this problem:

[INFO 240319 11:19:21] Using provider AnsibleTower for execution
[INFO 240319 11:19:21] Using token authentication
[INFO 240319 11:19:22] No inventory specified, Ansible Tower will use a default.
[WARNING 240319 11:19:22] Job uses non-json extra_vars:
    deploy_scenario: satellite-upgrade-source
    deploy_rhel_version: ''
    deploy_sat_version: ''
    deploy_snap_version: ''
    upgrade_path: ''
    snap_description: UMB created template by Jenkins Pipeline
 [...]
    Attempting to parse as pseudo-dictionary.
[INFO 240319 11:19:24] Waiting for job: 
[...]