Types sometimes get created with a first charater in upper case and sometimes not

[papegaaij]

This problem is especially visible in the Golang code where the comment for the constructor changes between:

// NewGroup instantiates a new group and sets the default values.
// NewGroup instantiates a new Group and sets the default values.

The actual code does not change, but the comments do. Running Kiota multiple times may even produce different results.

These changes come from two different parts of the code constructing the type name:

• OpenApiSchemaExtensions.GetSchemaNames: results in a verbatim copy of the last part of the reference id.
• OpenApiReferenceExtensions.GetClassName: converts the first character of the reference id to upper case.

These two routes should at least align. It seems the first is mostly like to end up in the type and also results in the cleanest documentation (the documentation will match the spec). Therefore I suggest to remove the ToFirstCharacterUpperCase() from the second: #2861