[V1] Remove V0 code paths for Hybrid models

[tdoublep]

Purpose

Remove V0 code path from the following models:

• Mamba1
• Mamba2
• Minimax (LinearAttention)
• LFM (ShortConv)
• Qwen3-Next (GDN)
• Bamba
• Jamba
• Nemotron-H
• GraniteMoeHybrid
• Plamo2
• Zamba
• Falcon-H

Please now that the model phi4flash has not been ported to V1 yet (#23996) and is non-trival to do so (requires porting differential attention backend). This PR removes the modeling code for that model. It can be re-added once the porting is done. The code will be useless until then anyway since V0 has been removed.

Test Plan

Hybrid model test should verify nearly all of the above. I have run it locally. Let's see what happens in CI.

Test Result

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• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
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