(fix) change how PancakeSwap fetches V2 pools

[fengtality]

Before submitting this PR, please make sure:

• Your code builds clean without any errors or warnings
• You are using approved title ("feat/", "fix/", "docs/", "refactor/")

A description of the changes proposed in the pull request:

• Changes PancakeSwap V2 pool fetch to include all V2 pools, not just stable pools
• Fixes [Bug] Pancakeswap router not returning valid routes for /amm/price #369

Tests performed by the developer:

• Tested with CAKE-USDT and verified that /amm/price returned same buy and sell prices as PancakeSwap UI

{
    "chain": "{{chain}}",
    "network": "{{network}}",
    "connector": "pancakeswap",
    "base": "CAKE",
    "quote": "USDT",
    "amount": "1",
    "side": "SELL"
}

Tips for QA testing:

[nikspz]

Test performed:

• Cloned and installed PR371 + Client latest dev branch
• connected pancakeswap_binance-smart-chain_mainnet and pancakeswap_ethereum_arbitrum successfully
• checked balance successfully
• checked amm/price : ok
• created/ started amm_arb using pancakeswap_binance-smart-chain_mainnet successfully
• amm/trade: ok