Tab keymap collision between nvim-cmp and copilot.vim in AstroNvim

I'm using AstroNvim, and just installed copilot.vim. It's working fine, except that I want to use the Tab key to accept a copilot suggestion. However, the Tab key is mapped to 'Next Completion' according to the AstroNvim docs. How do I disable this behavior so that the Tab key is only used for accepting Copilot suggestions?

I have tried adding the following code in my lua/plugins/cmp.lua file:

return {
  "hrsh7th/nvim-cmp",
  opts = function(_, opts)
    local cmp = require("cmp")
    opts.mapping["<Tab>"] = nil
  end
}

It hasn't had any effect however.

I used these snippets:

In cmp.lua:

return {
  "hrsh7th/nvim-cmp",
  opts = function(_, opts)
    local cmp = require("cmp")
    opts.mapping["<Tab>"] = nil
  end
}

In astrocore.lua:

return {
  "AstroNvim/astrocore",
  options = {...},
  mappings = {
    i = {
      ["<CR>"] = "copilot#Accept('\\<CR>')"
    }
  }
}