DataTable: support passing a function to the dataKey prop

[nestorrente]

I'm submitting a ... (check one with "x")

[x] bug report
[x] feature request
[ ] support request

This can be considered a bug report or a feature request, depending on the point of view.

CodeSandbox Case (Bug Reports)

https://codesandbox.io/s/purple-cloud-j8ehhg?file=/src/App.vue

Current behavior
The DataTable works as expected, but a warning is shown in the console:

[Vue warn]: Invalid prop: type check failed for prop "dataKey". Expected String with value "function () { [native code] }", got Function

Expected behavior

No warning.

Minimal reproduction of the problem with instructions

Instead of passing a String in the dataKey property, use a Function.

What is the motivation / use case for changing the behavior?

Sometimes a simple property is not enough for specifying the unique key of the items. For example, if you have a database table that uses a Composite PK, you will need to use 2 or more columns in order to get a unique identifier for each object.

If the dataKey property of the DataTable supports passing a function, the developer of the application will be able to indicate how that unique key must be generated, no matter how complex that logic is.

This is actually already supported, as the dataKey prop is evaluated using the ObjectUtils.resolveFieldData(data, field) method, which supports passing a function in the field parameter. However, as the prop is declared as String, Vue shows an annoying warning each time the component is rendered.

Please tell us about your environment:

• Vue version: 3.2.33
• PrimeVue version: 3.12.6
• Browser: all