[Bug]: Cannot start DAB when a table has a non-supported data type, even if the column has been added to the exclude list

### What happened?

My table is the following:

```sql
create table vehicle_position_data
(
id varchar(20) not null primary key clustered,
trip_id int not null,
direction_id int not null,
vehicle_id varchar(20) not null,
route_id int not null,
latitude decimal (9,6) not null,
longitude decimal (9,6) not null,
[position] as geography::Point(latitude, longitude, 4326) persisted,
[timestamp] int not null,
stop_info nvarchar(max) not null check(isjson(stop_info)=1)
)
go
```

The `geography` data type is not yet supported, so I added the `position` column to the excluded columns:

```json
"entities": {
"Positions": {
"source": "dbo.vehicle_position_data",
"permissions": [
{
"role": "anonymous",
"actions": [
{
"action": "*",
"fields": {
"exclude": [ "position" ]
}
}
]
}
],
"rest": {
"path": "/positions"
}
}
}
```

But I get the error:

```
Unable to complete runtime initialization. Refer to exception for error details.
Azure.DataApiBuilder.Service.Exceptions.DataApiBuilderException: Cannot obtain Schema for entity Positions with underlying database object source: dbo.vehicle_position_data due to: DataReader.GetFieldType(7) returned null.
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.GetTableWithSchemaFromDataSetAsync(String entityName, String schemaName, String tableName)
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.PopulateSourceDefinitionAsync(String entityName, String schemaName, String tableName, SourceDefinition sourceDefinition, String[] runtimeConfigKeyFields)
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.PopulateObjectDefinitionForEntities()
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.InitializeAsync()
at Azure.DataApiBuilder.Service.Startup.PerformOnConfigChangeAsync(IApplicationBuilder app)
```

Which is not expected as the column has been excluded.

### Version

0.7.5

### What database are you using?

Azure SQL

### What hosting model are you using?

Local (including CLI)

### Which API approach are you accessing DAB through?

REST

### Relevant log output

```Text
Information: Microsoft.DataApiBuilder 0.7.5+2f938a6dfe4b90c26d9e24352b38280cb6e66f15
Found config file: dab-config.development.json.
Found config file: dab-config.json.
Information: Using merged config file based on environment:dab-config.development.merged.json.
Information: User provided config file: dab-config.development.merged.json
Information: Setting default minimum LogLevel: Debug for Development mode.
Starting the runtime engine...
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
Using file dab-config.development.merged.json to configure the runtime.
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
GraphQL type for Positions is Positions
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
Runtime configuration has been successfully loaded.
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
GraphQL path: /graphql
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
StaticWebApps
info: Azure.DataApiBuilder.Service.Configurations.RuntimeConfigProvider[0]
Runtime config loaded from file.
info: Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager[63]
User profile is available. Using 'C:\Users\damauri\AppData\Local\ASP.NET\DataProtection-Keys' as key repository and Windows DPAPI to encrypt keys at rest.
info: Azure.DataApiBuilder.Service.Services.ISqlMetadataProvider[0]
Positions path: /api/Positions
fail: Azure.DataApiBuilder.Service.Startup[0]
Unable to complete runtime initialization. Refer to exception for error details.
Azure.DataApiBuilder.Service.Exceptions.DataApiBuilderException: Cannot obtain Schema for entity Positions with underlying database object source: dbo.vehicle_position_data due to: DataReader.GetFieldType(7) returned null.
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.GetTableWithSchemaFromDataSetAsync(String entityName, String schemaName, String tableName)
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.PopulateSourceDefinitionAsync(String entityName, String schemaName, String tableName, SourceDefinition sourceDefinition, String[] runtimeConfigKeyFields)
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.PopulateObjectDefinitionForEntities()
at Azure.DataApiBuilder.Service.Services.SqlMetadataProvider`3.InitializeAsync()
at Azure.DataApiBuilder.Service.Startup.PerformOnConfigChangeAsync(IApplicationBuilder app)
info: Azure.DataApiBuilder.Service.Startup[0]
Loading config file: dab-config.development.merged.json
fail: Azure.DataApiBuilder.Service.Startup[0]
Exiting the runtime engine...
crit: Microsoft.AspNetCore.Hosting.Diagnostics[6]
Application startup exception
System.ApplicationException: Could not initialize the engine with the runtime config file: dab-config.development.merged.json
at Azure.DataApiBuilder.Service.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env, RuntimeConfigProvider runtimeConfigProvider)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Span`1& arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.b__0(IApplicationBuilder builder)
at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass15_0.b__1(IApplicationBuilder app)
at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.g__MiddlewareFilterBuilder|0(IApplicationBuilder builder)
at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.b__0(IApplicationBuilder app)
at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken)
Unable to launch the runtime due to: System.ApplicationException: Could not initialize the engine with the runtime config file: dab-config.development.merged.json
at Azure.DataApiBuilder.Service.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env, RuntimeConfigProvider runtimeConfigProvider)
at System.RuntimeMethodHandle.InvokeMethod(Object target, Span`1& arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder)
at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.b__0(IApplicationBuilder builder)
at Microsoft.AspNetCore.Hosting.GenericWebHostBuilder.<>c__DisplayClass15_0.b__1(IApplicationBuilder app)
at Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter.<>c__DisplayClass0_0.g__MiddlewareFilterBuilder|0(IApplicationBuilder builder)
at Microsoft.AspNetCore.HostFilteringStartupFilter.<>c__DisplayClass0_0.b__0(IApplicationBuilder app)
at Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken)
at Microsoft.Extensions.Hosting.Internal.Host.StartAsync(CancellationToken cancellationToken)
at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token)
at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token)
at Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host)
at Azure.DataApiBuilder.Service.Program.StartEngine(String[] args)
Error: Failed to start the engine.
```

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Tái hiện lỗi khởi động với bảng Azure SQL được hiển thị và loại trừ entity trong dab-config. Bắt đầu tại SqlMetadataProvider.GetTableWithSchemaFromDataSetAsync, được xác định trong stack trace, và theo dõi quá trình khởi tạo schema cho cột position bị loại trừ. Hoàn tất khi runtime khởi động thành công mà không yêu cầu hỗ trợ cho cột geography bị loại trừ đó.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.