Expand nested content only for non array, maps

[ramya-rao-a]

Delve doesn't load strings or arrays or slices whose length is greater than 64. This value can be changed by using the setting dlvLoadConfig whose default values are as follows

	"go.delveConfig": {
		"dlvLoadConfig": {
			"followPointers": true,
			"maxVariableRecurse": 1,
			"maxStringLen": 64,
			"maxArrayValues": 64,
			"maxStructFields": -1
		}
	}

In #2198, we added the ability to expand nested content in the variables pane to fix #1010.

But while providing the feature to expand nested content, we also ended up expanding arrays and strings that have length > 64 if the said arrays/strings are children of one of the variable.

This PR restricts such expansion to just structs and interfaces

[jhendrixMSFT]

Not that I'm pushing back but curious what prompted this change?

[ramya-rao-a]

I had this point in my head the first time we went through your PR, but I hadnt sorted my thoughts yet and didnt get a chance to actually try the various scenarios.

Yesterday, I did get some time, and so the prompt for the change :)

[jhendrixMSFT]

Do you have a test case where you see it loading more than the 64 items? For me it only loads 64 even if there are more in the array. Maybe I need to update my test.

[ramya-rao-a]

Hmm... now that I check it, I do see that it loads only 64.

Do you have a test case, where we would need to expand the arrays/slices/maps ?
With mine, they expanded just fine even after the changes in this PR