fix(ui): improve select component behavior and styling across various providers

- Added a check to prevent empty values from being processed in the onValueChange handler for Bitbucket, Gitea, GitHub, and GitLab providers.
- Removed unnecessary defaultValue prop from Select components to streamline the code.
- Updated button styles to remove background color for better consistency across the UI.
- Enhanced volume backup selection to display a message when no volumes are found.

This update enhances user experience by ensuring that empty selections are handled gracefully and improves the overall visual consistency of the UI components.

apps/dokploy/components/dashboard/database/backups/handle-backup.tsx

@@ -409,7 +409,7 @@ export const HandleBackup = ({
 													<Button
 														variant="outline"
 														className={cn(
-															"w-full justify-between bg-input!",
+															"w-full justify-between",
 															!field.value && "text-muted-foreground",
 														)}
 													>

apps/dokploy/components/dashboard/database/backups/restore-backup.tsx

@@ -345,7 +345,7 @@ export const RestoreBackup = ({
 												<Button
 													variant="outline"
 													className={cn(
-														"w-full justify-between bg-input!",
+														"w-full justify-between",
 														!field.value && "text-muted-foreground",
 													)}
 												>
@@ -427,7 +427,7 @@ export const RestoreBackup = ({
 												<Button
 													variant="outline"
 													className={cn(
-														"w-full justify-between bg-input!",
+														"w-full justify-between",
 														!field.value && "text-muted-foreground",
 													)}
 												>