[PLUGIN-1895] Fixing datatype mismatch issue when value type is display

[prince-cs]

Current Issue:
It has been observed that when the display value type is selected, some values that are defined as integers in the schema appear as strings.

Code Changes:
The changes are made on how the schema is fetched. The API associated for fetching the schema is changed to use the column metadata api which now fetches the schema.
Schema API: baseUrl/api/now/doc/table/schema/tableName
Column Metadata API: baseUrl/api/now/ui/meta/tableName

In accordance with the response from the column metadata API, the SchemaResponse class is also changed to accommodate the changes. Before mapping the datatype, a check is applied that if the value type is display and if there is a mismatch between the internal_type and type then it needs to be mapped to the type otherwise internal_type.

Testing:
The code changes are verified by running unit tests and e2e tests. Also, did run the pipelines for some of the tables for Display and Actual value type.

JIRA Ticket: https://cdap.atlassian.net/browse/PLUGIN-1895

[itsankit-google]

please add some description in the PR,

with brief explanation under three subheadings:

• What is the current issue?

• What are the changes?

• How the changes are tested?

This will help reviewers understand the change and review PRs efficiently.

Also please create a JIRA and attached to every PR raised to open-source public repos.

[itsankit-google]

Also please don;t add reviewers until all these builds are green :

n/a