Add [Inject] to ZenjectSceneLoader Constructor

[zb-sj]

Inject Attribute is required for ConstructorChoiceStrategy.InjectAttribute

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• No compiler errors or warnings

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Issue Number

Issue Number: N/A

What is the current behavior?

• Validation fails and won't play with Zenject.ZenjectSceneLoader

ArgumentException: Type 'Zenject.ZenjectSceneLoader' does not have a default constructor

What is the new behavior?

• Validation passes and play as expected

Does this introduce a breaking change?

• Yes
• No

Other information

• 9.3.0 UPM Environmnet
• There might be other places which requires Inject Attribute

On which Unity version has this been tested?

• 2020.4 LTS
• 2020.3
• 2020.2
• 2020.1
• 2019.4 LTS
• 2019.3
• 2019.2
• 2019.1
• 2018.4 LTS

Scripting backend:

• Mono
• IL2CPP