[Doc]: Remove-AzPostgreSqlFlexibleServerDatabase issue

[dingmeng-xue]

Description

Example of Remove-AzPostgreSqlFlexibleServerDatabase should have whitespace before -InputObject

https://learn.microsoft.com/en-us/powershell/module/az.postgresql/remove-azpostgresqlflexibleserverdatabase?view=azps-9.2.0#example-2-remove-a-database-by-id