fix: differentiate similar schemas on completion

[p-spacek]

What does this PR do?

If multiple schemas inside of anyOf have the same final calculated schema name, 'parent/skeleton' autocompletion merge properties from different schema into one completion item.

wrong merge of multiple subschemas:

after fix:

note that a fixed example is not ideal. Schema creator should add titles into the schemas for a proper fix.

"leftElement": {
  "anyOf": [
    {
      "type": "object",
      "properties": { ... },
      "title": "Option 1"
    },
    {
      "type": "object",
      "properties": { ... },
      "title": "Option 2"
    },
   ...
  ]  

What issues does this PR fix or reference?

Is it tested? How?

modified Unit test

• the previous unit test doesn't make much sense

[coveralls]

Coverage decreased (-0.02%) to 81.492% when pulling 66cfbe0 on p-spacek:fix/differentiate-similar-schema into 360c038 on redhat-developer:main.

[gorkem]

lgtm