GET /slp/txDetails/{txid} return traceback data

[dtokens]

Call /slp/txDetails/d70af8576a059b24d831450ea9e4f6c192089212fc7469e3a51d2a771362e5d8 returns traceback data:

{
  "error": "TypeError: Cannot read property 'in' of undefined\n    at 
/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:1924:34\n    at step 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:43:23)\n    at Object.next 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:24:53)\n    at 
/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:18:71\n    at new Promise 
(<anonymous>)\n    at __awaiter 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:14:12)\n    at formatToRestObject 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:1917:12)\n    at 
/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:1844:42\n    at step 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:43:23)\n    at Object.next 
(/var/www/rest.bitcoin.com/dist/routes/v2/slp.js:24:53)"

}

[christroutner]

This issue needs further investigation:

• Clear steps on how to reproduce this issue
• What is the expected result?
• How is the actual result different than the expectation?

[christroutner]

The reason the traceback error message is displayed is because the TXID is not an SLP transaction.

Here is the endpoint which re-creates this issue:
https://rest.bitcoin.com/v2/slp/txDetails/d70af8576a059b24d831450ea9e4f6c192089212fc7469e3a51d2a771362e5d8

Here on the block explorer you can see that this is not an SLP transaction:
https://explorer.bitcoin.com/bch/tx/d70af8576a059b24d831450ea9e4f6c192089212fc7469e3a51d2a771362e5d8

[christroutner]

The scope of this issue is update the /v2/slp/txDetails/ endpoint to return an error message like 'not an slp transaction' in this scenario. Any PR fixing this issue should include unit and integration tests for this use case.