Fix bug reading with 'tagged' variants when a variant is non-copyable

[jmcken8]

Added a test. Needed to change the test to emplace each element rather than initializer_list due to the non-copyable element.

[gemini-code-assist]

Summary of Changes

Hello @jmcken8, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a critical bug that prevented the correct reading of 'tagged' variants when one of the variant's alternative types was non-copyable. The fix involves a subtle but important change in the internal parsing mechanism to allow for proper movement of such types, complemented by a new, robust test case that specifically validates this scenario.

Highlights

• Bug Fix: Non-copyable Variant Parsing: Corrected the parsing logic within rfl::parsing::Parser_rfl_variant.hpp to properly handle rfl::Variant types that contain non-copyable members. This was achieved by changing a lambda parameter from const auto& to auto&, enabling std::move to correctly transfer ownership of non-copyable elements during deserialization.
• New Test Case for Non-copyable Types: Introduced a new test scenario in test_add_tag_to_rfl_variant.cpp by modifying the button_released_t struct to include an rfl::Box<int> member, which is a non-copyable type. This ensures that the fix addresses the specific issue of reading variants with non-copyable elements.
• Test Initialization Adaptation: Updated the test case in test_add_tag_to_rfl_variant.cpp to use std::vector::emplace_back for populating the test data. This change was necessary because the button_released_t struct now contains a non-copyable member, and emplace_back allows for in-place construction without requiring copy or move constructors for the elements themselves.

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[gemini-code-assist]

Code Review

This pull request fixes a bug in reading tagged variants with non-copyable types. The fix correctly enables moving the value from the variant. A suggestion has been provided to make the code more robust.

[liuzicheng1987]

@jmcken8 , makes sense. Thank you for the contribution!