Microsoft.Data.Sqlite: Avoid re-initialization of pooled connections

[bricelam]

This simple benchmark goes from 5078 ms to 124.

using Dapper;
using Microsoft.Data.Sqlite;

using var connection = new SqliteConnection(
    "Data Source=test.db;Password=Password12!");

connection.Execute(
    "CREATE TABLE IF NOT EXISTS Data(Value)");

for (var i = 0; i < 10; i++)
{
    connection.Execute(
        "INSERT INTO Data VALUES (@Value)",
        new { Value = Random.Shared.Next() });
}

Fixes #28774