Make member role application command a hybrid slash command

[johnvictorfs]

Motivation

• Only the member-role apply flow should be exposed as the slash aplicar command while PvM apply flows (Raids/AoD) must remain prefix-only to avoid changing unrelated behaviors.
• Preserve the ranks hybrid behavior and keep a helpful suggestion when invoked via prefix for a better UX.
• Update tests and stubs so the authentication cog can be validated in isolation.

Description

• Converted the member-role apply command to a hybrid command by changing the decorator to @commands.hybrid_command(name="aplicar", aliases=["role", "membro", "aplicar_role"]) in bot/cogs/authentication.py.
• Reverted the raids apply command to a normal prefix command with @commands.command("raids", aliases=["aplicar_raids"]) in bot/cogs/chat.py so PvM apply commands remain unchanged.
• Kept ranks as a hybrid command and preserved the prefix-tip by checking if getattr(ctx, "interaction", None) is None: await ctx.send("Dica: use o comando de barra /ranks ...") in bot/cogs/clan.py.
• Extended tests/helpers.py with additional lightweight stubs and a make_authentication() helper, replaced the aplicar test to assert authentication.aplicar_role is a HybridCommand, and kept/added tests/test_ranks_command.py to validate ranks hybrid behavior and the prefix suggestion.

Testing

• Ran the full test suite with pytest -q, which completed successfully with 5 passed.

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