Skip service role when all deploy prefs with no role are disabled

[hawflau]

Issue #, if available:
#1496

Description of changes:
This PR modifies the translated templates output by sam-translator in order to make sure that no unnecessary CodeDeployServiceRole is created. If there is a deployment preference which has no role (but that's okay because it's disabled), then the role will not be created.

I went for the easiest win, which was changing the logic in can_skip_service_role. Do we feel like that is the best place? Alternatively, I think we could modify self._resource_preferences.values() so that disabled DeploymentPreferences are not present.

There are some broken unit tests on this branch but it looks like those are broken on develop too right now, so I don't believe that was introduced by this change.

Description of how you validated changes:
By running bin/translate-sam.py by hand, and by adding unit tests.

Checklist:

• Add/update tests using:
  • Correct values
  • Bad/wrong values (None, empty, wrong type, length, etc.)
  • Intrinsic Functions
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected

Examples?

Please reach out in the comments, if you want to add an example. Examples will be
added to sam init through https://github.com/awslabs/aws-sam-cli-app-templates/

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

[codecov-commenter]

Codecov Report

Merging #2187 (996c307) into develop (cb8e179) will increase coverage by 0.29%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #2187      +/-   ##
===========================================
+ Coverage    94.08%   94.38%   +0.29%     
===========================================
  Files           86       95       +9     
  Lines         5413     6534    +1121     
  Branches      1082     1317     +235     
===========================================
+ Hits          5093     6167    +1074     
- Misses         148      170      +22     
- Partials       172      197      +25     

Impacted Files	Coverage Δ
...el/preferences/deployment_preference_collection.py	93.20% <ø> (+1.84%)	⬆️
samtranslator/region_configuration.py	77.77% <0.00%> (-22.23%)	⬇️
samtranslator/sdk/resource.py	90.00% <0.00%> (-10.00%)	⬇️
samtranslator/validator/validator.py	90.56% <0.00%> (-5.09%)	⬇️
samtranslator/plugins/api/implicit_api_plugin.py	94.08% <0.00%> (-4.17%)	⬇️
samtranslator/model/s3_utils/uri_parser.py	69.23% <0.00%> (-2.20%)	⬇️
samtranslator/translator/translator.py	97.26% <0.00%> (-1.17%)	⬇️
samtranslator/model/sam_resources.py	92.35% <0.00%> (-1.01%)	⬇️
...lator/plugins/application/serverless_app_plugin.py	82.73% <0.00%> (-0.82%)	⬇️
samtranslator/model/__init__.py	97.64% <0.00%> (-0.51%)	⬇️
... and 42 more

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[marekaiv]

Based on the description and code change, we're trying to handle the case where Enabled is false and no role is specified -- is this correct? If so, should we omit role from the test case?

[hawflau]

Closing this one in favor of #2197