Fixed length binary columns in user defined table types fail when constructed

Issue Summary

When using a user defined table type with a fixed length binary column the wrong constructor for SqlMetaData is used resulting in the following exception.

System.ArgumentException: 'The dbType Binary is invalid for this constructor.'

This line looks like it's causing the issue, which incorrectly assumes if it is a fixed length that it can safely use the two parameter constructor:

https://github.com/fsprojects/FSharp.Data.SqlClient/blob/0bc5129586512316570da1f27e588287d7e8be35/src/SqlClient.DesignTime/DesignTime.fs#L544

To Reproduce

1. Create a custom table type

CREATE TYPE [dbo].[CustomTableType] AS TABLE(
	[Value] [binary](16)
)

2. Use the type in a query

type StaticProvider =
    SqlCommandProvider<"
        Declare @Updates as CustomTableType = @Inputs;
    " , staticConnectionString>

use cmd = new StaticProvider(context.connection, transaction = context.transaction)
cmd.AsyncExecute(
    data.inputs
    |> List.map(fun x ->
        StaticProvider.CustomTableType( // <--- Error in constructor
            Value = x.value
        )
    )

Error

System.ArgumentException: 'The dbType Binary is invalid for this constructor.'

Expected behavior

There should not be an error in this case.

What you can do

• I am willing to contribute a PR with a unit test showcasing the issue
• I am willing to test the bug fix before next release

Start by reading src/SqlClient.DesignTime/DesignTime.fs around line 544 and reproduce the supplied custom table type using a binary(16) column. Add a regression unit test for constructing the generated table-type value, then verify that it completes without the reported SqlMetaData constructor exception.