fix(kubernetes): handled missing key in k8s templates

[PelegLi]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

handled empty field "spec" in k8s templates.
No UT for this specific case wasn't added since a YAML with null value is not parsed in checkov (considered as a parsing error)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[gruebel]

Suggested change

	if "spec" in conf and "jobTemplate" in conf["spec"] and "spec" in conf["spec"]["jobTemplate"] and conf["spec"]["jobTemplate"]["spec"] and "template" in conf["spec"]["jobTemplate"]["spec"] and "spec" in conf["spec"]["jobTemplate"]["spec"]["template"]:
	spec = conf["spec"]["jobTemplate"]["spec"]["template"]["spec"]
	cron_spec = find_in_dict(input_dict=resource, key_path="spec/jobTemplate/spec/template/spec")
	if isinstance(cron_spec, dict):
	spec = cron_spec

you can import this function from

from checkov.common.util.data_structures_utils import find_in_dict

this will take care of any weird None value along the line