Related Feature Request

Relates to feature request: [Improve mget method implementation using Java 8 Streams]

Description

This PR refactors the mget method in RedisAdvancedClusterReactiveCommandsImpl.java to improve code readability and maintainability by utilizing Java 8 Streams and reactive programming patterns.

Current Implementation Issues

• Uses manual for loops to build publisher list
• Complex nested iteration structure
• Less readable code for handling partitioned data
• Uses flatMapIterable instead of more idiomatic reactive approach

Proposed Changes

• Replaced manual publisher list creation with Stream API
• Simplified partition handling using functional approach
• Improved reactive chain using flatMapMany(Flux::fromIterable)
• Maintained same functionality with cleaner implementation

Implementation Details

• Replaced for loop with partitioned.values().stream().map(super::mget)
• Streamlined result processing using reactive chain
• Maintained backward compatibility with existing API
• No changes to public interfaces

closes #3060