The FT metadata endpoint does not return asset id in the response when used with a testnet address, unlike a mainnet address

**Describe the bug**
The FT metadata endpoint does not return asset id in the response when used with a testnet address, unlike a mainnet address.
This is causing issues with the explorer that expects to get the asset id with testnet addresses the same way it gets them for mainnet addresses.

Also, the stacks api docs for the ft metadata endpoint will not work with testnet addresses

**To Reproduce**
Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior**
I expect the endpoint to work the same for both testnet and mainnet addresses. They should both return the asset id.

**Screenshots**

**Console log**
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**Desktop (please complete the following information):**
- OS: [e.g. iOS]
- Browser [e.g. chrome, safari]
- Version [e.g. 22]

**Smartphone (please complete the following information):**
- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Additional context**
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