@default directive accepts invalid values

[islamaliev]

Add a schema with invalid default value:

$ defradb client schema add 'type User { name: String, active: Boolean @default(bool: blah)}'

It competes without errors. When you create a doc arterwards:

$ defradb client collection create '{ "name": "John" }'

You get a panic:

panic: interface conversion: interface {} is string, not bool

goroutine 1 [running]:
github.com/sourcenetwork/defradb/client.getBool({0x108e5b540?, 0x14001d5bcd0?})
	github.com/sourcenetwork/defradb/client/document.go:386 +0x94
github.com/sourcenetwork/defradb/client.validateFieldSchema({0x108e5b540, 0x14001d5bcd0}, {{0x14001d71d68, 0x6}, 0x1, {0x10972cfb8, 0x10bd71590}, {0x0, 0x0}, 0x1, ...})
	github.com/sourcenetwork/defradb/client/document.go:291 +0xa58
github.com/sourcenetwork/defradb/client.(*Document).Set(0x140012151e0, {0x14001d71d68, 0x6}, {0x108e5b540, 0x14001d5bcd0})
	github.com/sourcenetwork/defradb/client/document.go:736 +0x53c
github.com/sourcenetwork/defradb/client.(*Document).setDefaultValues(0x140012151e0)
	github.com/sourcenetwork/defradb/client/document.go:778 +0xb8
github.com/sourcenetwork/defradb/client.newEmptyDoc({{{0x1, {0x14001d71ad0, 0x4}}, 0x1, 0x1, {0x14001d82340, 0x3b}, {0x10beea120, 0x0, 0x0}, ...}, ...})
	github.com/sourcenetwork/defradb/client/document.go:109 +0xa8
github.com/sourcenetwork/defradb/client.NewDocFromJSON({_, _, _}, {{{0x1, {0x14001d71ad0, 0x4}}, 0x1, 0x1, {0x14001d82340, 0x3b}, ...}, ...})
	github.com/sourcenetwork/defradb/client/document.go:170 +0x4c
github.com/sourcenetwork/defradb/cli.MakeCollectionCreateCommand.func1(0x14001d65208, {0x14001d5aa80?, 0x1?, 0x107f2b1bc?})
	github.com/sourcenetwork/defradb/cli/collection_create.go:100 +0x26c
github.com/spf13/cobra.(*Command).execute(0x14001d65208, {0x14001d5aa50, 0x1, 0x1})
	github.com/spf13/[email protected]/command.go:985 +0x840
github.com/spf13/cobra.(*Command).ExecuteC(0x14001d6db08)
	github.com/spf13/[email protected]/command.go:1117 +0x344
github.com/spf13/cobra.(*Command).Execute(0x10bd03388?)
	github.com/spf13/[email protected]/command.go:1041 +0x1c
main.main()
	github.com/sourcenetwork/defradb/cmd/defradb/main.go:23 +0x20

Note:
With not matching types:

$ defradb client schema add 'type User { name: String, age: Int @default(int: "1")}'

It doesn't panic:

$ defradb client collection create '{ "name": "John" }'
Error: unexpected type. Property: field, Expected: int64, Actual: string

But it needs to be caught on schema creation.