Fix unhandled error when match_all/match_any format is incorrect

[unnawut]

Issue/Task Number: #975
Closes #975

Overview

Fixes the internal server error returned when the provided with an invalid match_all/match_any filter attributes.

Changes

• MatchParser rejects filter attributes that are invalid (i.e. not in a list).
• Updated :missing_filter_param error description to "Invalid parameter provided. Expecting an array of filter parameters." for clarity

Implementation Details

Server was crashing because Enum.reduce_while/3 could be enumerated both over a list or a map. Since the expected value is a list, but a map could easily be mistaken (using only 1 set of filter, passed that set without wrapping in a list), this will be caught now before being handled.

Did this instead of supporting a single filter without list to keep the API consistent.

Usage

Request:

curl -X POST http://localhost:4000/api/admin/token.all \
-X POST \
-H "Accept: application/vnd.omisego.v1+json" \
-H "Authorization: OMGProvider <truncated>" \
-H "Content-Type: application/json" \
-d '{
  "match_all": {
    "comparator": "eq",
    "field": "symbol",
    "value": "ABC"
  }
}' \
-v -w "\n"

Response:

{
  "version": "1",
  "success": false,
  "data": {
    "object": "error",
    "messages": {},
    "description": "Invalid parameter provided. Expecting an array of filter parameters.",
    "code": "client:invalid_parameter"
  }
}

Impact

No changes to DB schema or API specs.