fix: panic in spew when dealing with unexported fields

[ccoVeille]

Summary

Fix panic that happens when spew tries to sort unexported fields

Changes

Fix the panic raised by Interface() on unexported fields

CanInterface() is the solution

Motivation

Now, go-spew is vendored, we can fix old issues we had

Related issues

• Related to go-spew vendoring #1826
• Closes Panic in assert/require.Equal when calling into go-spew #480
• Closes assert.Equal panic on diff unexported map with array as key #1813
• Closes don't panic on unexported struct key in map #1816
• Supersedes Catch panic when using go-spew #1824