Handle avatar upload fail

[pinarol]

Closes https://github.com/Automattic/Gravatar-SDK-iOS/issues/347

Description

• Adds error style for the toast
• Replaces "Got it" with "X" icon
• Shows error toast when upload fails
• Adds a retry button on the failed image
• Shows error toast when avatar selection fails

https://github.com/user-attachments/assets/e583fd53-afc9-4b8a-8734-7c1693861c16

Testing Steps

• SwiftUI Demo app > Avatar Picker View. You can disconnect from internet and try uploading image and changing your avatar.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Gravatar SwiftUI Prototype Build by scanning the QR code below to install the corresponding build.

	App Name	Gravatar SwiftUI Prototype Build
	Build Number	1097
	Version	1.0
	Bundle ID	com.automattic.gravatar-sdk-demo-swiftui.prototype-build
	Commit	6efae9c2ae1ccfa9ff5d4c9788c7d7f8b66fc2a8
	App Center Build	Gravatar SDK Demo - SwiftUI #39

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Gravatar UIKit Prototype Build by scanning the QR code below to install the corresponding build.

	App Name	Gravatar UIKit Prototype Build
	Build Number	1097
	Version	1.0
	Bundle ID	com.automattic.gravatar-sdk-demo-uikit.prototype-build
	Commit	6efae9c2ae1ccfa9ff5d4c9788c7d7f8b66fc2a8
	App Center Build	Gravatar SDK Demo - UIKit #41

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[pinarol]

Invalid frame dimension (negative or non-finite).

Gosh my XCode doesn't show me those errors inline. Seems like that line is not necessary anyway so I fixed it by just removing it.