Remove Backend tx-service calls

[DiogoSoaress]

Description

Remove tx-service direct calls.

There are 3 places where we are using BE tx-service endpoints. These should be converted to use the CGW.

Places to modify:

• Fetching the tokens asset list: getTokensServiceUrl().
  Add a function to the gateway-sdk. We will likely have to update the way in which type Token = RecordOf<TokenProps> are created from Redux.
• Get decoded data: getDataDecoderUrl()
  Add a function to the gateway-sdk
• Get master copies: getMasterCopiesUrl()

Instead all these call should go through the CGW.

• Decoded data
• Slack thread with more details

[iamacook]

I believe we are using transactionService (returned from the CGW) as intended now: fetching tokens, master copies and data decoder. We fetch all transactions from /chains. @katspaugh

Safe Apps use it for their communicator and iframe message handler. Can you confirm if this is correct @mikheevm?

[mmv08]

Safe Apps use it for their communicator and iframe message handler. Can you confirm if this is correct @mikheevm?

This is correct, but it was used only in older versions and we keep it only for backward compatibility. After we implement safe-global/safe-apps-sdk#255 we'll check if we can remove it

[jpalvarezl]

Just to be totallly certain this is necessary, the CGW generally returns TokenInfo within the transaction response. It would be good to know whether having a dedicated token endpoint is even necessary. Maybe this can get removed entirely without the need for an endpoint.

[iamacook]

It would be good to know whether having a dedicated token endpoint is even necessary.

It appears to not be being used at all. I've removed the redundant code in the linked PR.

[francovenica]

@katspaugh can we close this one?

[katspaugh]

Yes. Thanks!