Update icrc1_ledger_setup.mdx to avoid error messages when the user tries to follow the instructions

[yvonneanne]

Without this change, the user will see the following error:

% dfx identity use default
error: failed to parse /.../icrc1_ledger_canister/dfx.json as json
error:     caused by: expected value at line 5 column 17

[yvonneanne]

Similarly on

https://internetcomputer.org/docs/current/developer-docs/defi/tokens/indexes

"icrc1_index_canister": {
"type": "custom",
"candid": "https://raw.githubusercontent.com/dfinity/ic/d87954601e4b22972899e9957e800406a0a6b929/rs/rosetta-api/icrc1/index-ng/index-ng.did",
"wasm": "https://download.dfinity.systems/ic/d87954601e4b22972899e9957e800406a0a6b929/canisters/ic-icrc1-index-ng.wasm.gz",
}

the last comma should be removed