Feat/improve test error messages

[namanyadav-08]

Fixes #412

What does this PR do?

The test command was printing the same generic error message
for three different missing arguments, giving users no indication
of which specific argument was missing or what format it expects.

Before this fix

test command require apiName:apiVersion args
test command require apiName:apiVersion args
test command require apiName:apiVersion args

After this fix

missing required argument: apiName:apiVersion (e.g. 'my-api:1.0')
missing required argument: (e.g. 'http://localhost:8080/api')
missing required argument: (e.g. 'HTTP', 'POSTMAN', 'OPEN_API_SCHEMA')

Why this matters

Better error messages = faster debugging. Users immediately know
exactly which argument is missing and what format is expected,
without having to read the docs.

How to verify

Run the test command with missing arguments:

microcks test
microcks test my-api:1.0
microcks test my-api:1.0 http://localhost:8080

Each should now show a specific, helpful error message.