add uniswap for arbitrum

Since arbitrum class inherits from L1 class, by removing the custom
payment method integration, arbitrum now uses the same payment choices
as L1 (which includes uniswap)

pretix_eth/network/tokens.py

@@ -332,38 +332,6 @@ class Arbitrum(L1):
     CHAIN_ID = 42161
     NETWORK_UNISWAP_NAME = "arbitrum"
 
-    def payment_instructions(
-        self, wallet_address, payment_amount, amount_in_token_base_unit
-    ):
-        """
-        Generic instructions for paying on all Arbitrum networks (eg Rinkeby and Mainnet),
-        both for native tokens and custom tokens.
-
-        Pay via a web3 modal, ERC 681 (QR Code) or manually.
-        """
-        erc_681_url = make_erc_681_url(
-            to_address=wallet_address,
-            payment_amount=payment_amount,
-            chain_id=self.CHAIN_ID,
-            is_token=not self.IS_NATIVE_ASSET,
-            token_address=self.ADDRESS,
-        )
-        amount_manual = f"{amount_in_token_base_unit} {self.TOKEN_SYMBOL}"
-        web3modal_url = make_checkout_web3modal_url(
-            currency_type=self.TOKEN_SYMBOL,
-            amount_in_ether_or_token=amount_in_token_base_unit,
-            wallet_address=wallet_address,
-            chainId=self.CHAIN_ID,
-        )
-
-        return {
-            "erc_681_url": erc_681_url,
-            # "uniswap_url": None,
-            "web3modal_url": web3modal_url,
-            "amount_manual": amount_manual,
-            "wallet_address": wallet_address,
-        }
-
 
 class RinkebyArbitrum(Arbitrum):
     """