Fix naming inconsistency of McpClientTransport implementations

[quaff]

Currently, we have HTTP McpClientTransport implementations:

• HttpClientSseClientTransport
• HttpClientStreamableHttpTransport
• WebFluxSseClientTransport
• WebClientStreamableHttpTransport

WebFluxSseClientTransport should be renamed to WebClientSseClientTransport or WebClientStreamableHttpTransport should be renamed to WebFluxStreamableHttpTransport.

See GH-450 for more background.

[chemicL]

Due to #127 being actively worked on, @tzolov let's perhaps address this in spring-ai 2.0?

@quaff this will not be addressed in the Java SDK as these types will not be part of the offering and will have moved to Spring AI.