[iotax_getCoinMetadata) Always returns "null" for Coin created with Coin manager

[philou-078]

see thread : https://discord.com/channels/912718559954747442/1282243183648178208/1346788047512932353

[Thoralf-M]

To reproduce

curl https://api.testnet.iota.cafe \
--header 'content-type: application/json' \
--data '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "iotax_getCoinMetadata",
    "params": {
        "coin_type": "0xf1b0e9a71fe76d6264a494f048c20df42c0771e9e9664a5409df573aee1482c4::token::TOKEN"
    }
}' | jq .

The CoinManager object https://explorer.rebased.iota.org/object/0x1768de9f9ef6d7e3d811ed14c8dc56d23c1117a183f3e671b5cf3c5634d4706d

[kodemartin]

CoinReadApi::get_coin_metadata seeks for the 0x2::coin::CoinMetadata object among the created objects in the transaction that published the associated package.

However with the introduction of 0x2::coin_manager::CoinManager the metadata object can be wrapped inside the CoinManager.

The respective implementations in iota-indexer and iota-json-rpc should be adjusted to seek for CoinManager objects and get the wrapped metadata in case the CoinMetadata object is not found.