Simplify construction of MeilisearchClient in DI

[ahmednfwela]

Pull Request

Related issue

Fixes part of #481, which is the inability to use .AddHttpMessageHandler<MeilisearchMessageHandler>()

What does this PR do?

• Adds default constructor for MeilisearchMessageHandler
• Refactor MeilisearchClient constructors to call one another, instead of redefining the logic in both.

PR checklist

Please check if your PR fulfills the following requirements:

• Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
• Have you read the contributing guidelines?
• Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!

[brunoocasali]

Hey @ahmednfwela how can I check if this change does the trick?! 😬

Is there a way to add tests or something? If not possible, let's merge anyway!

[ahmednfwela]

@brunoocasali The constructor change of MeilisearchClient is already covered by tests
and the MeilisearchMessageHandler constructor doesn't need tests, as long as it compiles.

[ahmednfwela]

We can add a new package to the repository to help with DI scenarios, that will be based on this comment #481 (comment).

[brunoocasali]

I don't think it is needed unless you say so! You can merge this if you want!

[ahmednfwela]

bors merge

[meili-bors]

Build succeeded:

• format-check
• integration-tests