fix: remove outdated jdtls progress message handler (#2897)

[s1n7ax]

progress message

before

After

[github-actions]

Do not change server_configurations.md directly. Edit the lua source file instead. See https://github.com/neovim/nvim-lspconfig/blob/master/CONTRIBUTING.md#generating-docs

[s1n7ax]

May be that screenshots are misleading. in the bottom right, noice.nvim displays the progress status by overriding vim.lsp.handlers['$/progress']. Before, jdtls had defined a handler withing the config so it never reached noice.nvim. nil in the first screenshot was printed by the jdtls config $/progress handler.