Move some the feasible functionality of the 'ExperimentPageContentService' class into a newly created java class as this class constructor is growing with many dependencies.

[ke4]

• ExperimentPageContentService currently has 8 DI classes as part of its constructor.
• This makes the class hard to maintain and hard to test, as we need to inject mocks for all DI classes to write tests.
• So, the feasible solution would be that let's move some functionality into a newly created class and write tests.
• That way we can reduce some burden on ExperimentPageContentService or we can make the class easy to manage and test.