fix(haskell): remove now redundant discover_configurations call

[mrcjkb]

📑 Description

• Since version 2.1.0, haskell-tools.nvim automatically discovers DAP launch configurations if both nvim-dap and haskell-debug-adapter are installed.
• See fix(haskell): Update haskell-tools.nvim to v2.0.0 #553 (comment)

@Uzaaft @Per48edjes

ℹ Additional Information

The 2.1.0 change is backward compatible, but the discover_configurations call is now redundant.

[github-actions]

Review Checklist

Does this PR follow the [Contribution Guidelines](development guidelines)? Following is a partial checklist:

Proper conventional commit scoping:

• If you are adding a new plugin, the scope would be the name of the category it is being added into. ex. feat(utility): added noice.nvim plugin

• If you are modifying a pre-existing plugin or pack, the scope would be the name of the plugin folder. ex. fix(noice-nvim): fix LSP handler error

• Pull request title has the appropriate conventional commit type and scope where the scope is the name of the pre-existing directory in the project as described above

• README is properly formatted and uses fenced in links with <url> unless they are inside a [title](url)

• Proper usage of opts table rather than setting things up with the config function.