[mlir][bufferization] Should `AllocationOpInterface::buildDealloc` be utilized somewhere in `buffer-deallocation-pipeline`?

The old, now removed, `buffer-deallocation` pass used to utilize the `AllocationOpInterface::buildDealloc` method so that users could have more control over how they dealloc memory that is allocated by an op in their own dialect. However, the `buffer-deallocation-pipeline` does not use this and the result is that it's not as easily extensible to custom dialects. Instead, the `populateBufferizationDeallocLoweringPattern` takes a `DeallocHelperMap` which to be honest I have a hard time understanding how this is supposed to work. The builtin `LowerDeallocationsPass` just populates this map using `bufferization::buildDeallocationLibraryFunction`, which I also find to be a bit confusing.

Before, it was so much simpler for users to specify their own dealloc while being able to use builtin passes unmodified (`buffer-deallocation`). Now it seems impossible with `buffer-deallocation-pipeline`. Please correct me if I'm wrong, but it seems like a user would have to define their own `DeallocHelperMap` and use `populateBufferizationDeallocLoweringPattern`. But if they do this then they can't take advantage of the `buffer-deallocation-pipeline` and would have to create their own.

I much prefer being able to use builtin passes that have been tested and vetted by people much more knowledgable about bufferization than I am. And I thought it was really nice that `buildDealloc` worked in tandem with `buffer-deallocation` pass. It would be great to treat `buffer-deallocation-pipeline` the same. Would it be a valid solution to just replace [this](https://github.com/llvm/llvm-project/blob/ecfdf8cb05d13e3be44a4c03adfe2771deb08edd/mlir/lib/Dialect/Bufferization/Transforms/LowerDeallocations.cpp#L67) `memref::DeallocOp` hardcoding with `buildDealloc`? I'm sure this wouldn't be the only change, but I'm just wondering if `buildDealloc` would be an appropriate use here. It seems like it isn't really used at all anymore.

Thanks!