Make (un)subscribe and filter RPC methods require only read perm

[fridrik01]

Fixes: #10682

Context
This PR changes the API permission of eth_subscribe/eth_unsubscribe and all eth filter methods to only require read permission instead of write permission.

Test Plan

Build generated files:

make gen

Pick eth_subscribe to test, replicated the perm error before applying this PR:

wscat --connect ws://localhost:1234/rpc/v1 
Connected (press CTRL+C to quit)
> {"jsonrpc":  "2.0",  "id":  1,  "method":  "eth_subscribe",  "params":  ["newHeads"]}
< {"jsonrpc":"2.0","id":1,"error":{"code":1,"message":"missing permission to invoke 'EthSubscribe' (need 'write')"}}

After applying this PR, then it goes through:

wscat --connect ws://localhost:1234/rpc/v1 
Connected (press CTRL+C to quit)
> {"jsonrpc":  "2.0",  "id":  1,  "method":  "eth_subscribe",  "params":  ["newHeads"]}
< {"jsonrpc":"2.0","result":"0x46d6940586e840e9abbf304fab4678d200000000000000000000000000000000","id":1}

< {"jsonrpc":"2.0","method":"eth_subscription","params":{"subscription":"0x46d6940586e840e9abbf304fab4678d200000000000000000000000000000000","result":{"hash":"0x4e34f7a21c0ee8b3ac70dfbe73c87f37a016f1c640e7bda8752fe0ae798209f8","parentHash":"0x8709fe49b800cd389d3b6123ef2e8d03abb3249f8347c72e5c068fb378faf1f0","sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","miner":"0x0000000000000000000000000000000000000000","stateRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","transactionsRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","receiptsRoot":"0x0000000000000000000000000000000000000000000000000000000000000000","logsBloom":"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff","difficulty":"0x0","totalDifficulty":"0x0","number":"0x2b3000","gasLimit":"0x2540be400","gasUsed":"0x1c85a017a","timestamp":"0x6453d860","extraData":"0x","mixHash":"0x0000000000000000000000000000000000000000000000000000000000000000","nonce":"0x0000000000000000","baseFeePerGas":"0x20373cf","size":"0x0","transactions":[{"chainId":"0x13a","nonce":"0x3c18b","hash":"0x7768e8d1fa5d46c7a27c03a1efc0950f5d2d043028e1477da74b7c0fea672d5d","blockHash":"0x4e34f7a21c0ee8b3ac70dfbe73c87f37a016f1c640e7bda8752fe0ae798209f8","blockNumber":"0x2b3000","transactionIndex":"0x0","from":"0xff000000000000000000000000000000001e02b8","to":"0xff00000000000000000000000000000000000005","value":"0x0","type":"0x2","input":"0x","gas":"0x12c1a6db","maxFeePerGas":"0x9787c21","maxPriorityFeePerGas":"0x2d755f","accessList":[],"v":"0x0","r":"0x0","s":"0x0"},{"chainId":"0x13a","nonce":"0x11737","hash":"0x3f770b3c026f6db328fb99418882145713f17c9d0769812186083bcee123756c","blockHash":"0x4e34f7a21c0ee8b3ac70dfbe73c87f37a016f1c640e7bda8752fe0ae798209f8","blockNumber":"0x2b3000","transactionIndex":"0x1","from":"0xff000000000000000000000000000000001ea34
...

[raulk]

SGTM because these methods are read-only (although the create state in memory, e.g. filter or subscription). However, as reported in issues, perm:write is the wrong permission here since hosted RPC nodes use read users to call from their gateways into Lotus, which prevents those RPC nodes from ever offering these operations.

If nodes want to limit/block such operations, they can do it elsewhere (frontend).