fix(picker): enforce bottom positioning for quickfix and location lists

[Isrothy]

Description

This PR addresses an issue where the quickfix list (qflist) would open on the left side of the screen when using vertical splits. By replacing the default :copen command with :botright copen, this update ensures that the qflist consistently opens at the bottom, regardless of the current window layout.

Reproduce:

1. Open Neovim: Start Neovim normally.
2. Create a Vertical Split
3. Use picker to pick anything
4. Press to send them to quickfix list

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

vim.g.mapleader = " "

require("lazy.minit").repro({
	spec = {
		{
			"Isrothy/snacks.nvim",
			branch = "bottom-positioning-for-qf",
			lazy = false,
			keys = {
				{
					"<LEADER>ff",
					function()
						Snacks.picker.files()
					end,
					desc = "Files",
				},
			opts = {},
		},
		-- add any other plugins here
	},
})

Screenshots

before:

after:

[folke]

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