Disable user liquidity completely

[gztensor]

• Make swap::add_liquidity extrinsic to always return UserLiquidityDisabled
• In disable_lp function do not stop early if do_dissolve_all_liquidity_providers returns error.

Acceptance criteria:

Setup: Create subnet on devnet with Charlie (sn4).

• Extrinsic swap::add_liquidity(4, 100000) called by Charlie returns UserLiquidityDisabled
• Extrinsic swap::add_liquidity(4, 100000) called by Alice returns UserLiquidityDisabled
• Extrinsic swap::toggle_user_liquidity(4, True) called by Charlie succeeds, but has no effect (swap::enabledUserLiquidity(4) map remains False).
• The Positions map only returns protocol liqudity positions (to ensure do_dissolve_all_liquidity_providers will have no effect even if it fails)