[11.x] Add overwrite confirmation to environment encryption commands

[dxnter]

Adding minor improvements to both the env:encrypt and env:decrypt commands that prompt the user if they would like to overwrite the existing decrypted/encrypted environment file in the absence of the --force option.

This pull request also resolves a minor misalignment in EnvironmentDecryptCommandTest, where the assertions being made in testItFailsWhenEncryptionFileCannotBeFound() and testItFailsWhenEnvironmentFileExists() were incorrectly interchanged.

[taylorotwell]

I think this is OK for now as it remains consistent with the other generation commands.

[dxnter]

@taylorotwell Understandable, this was mostly inspired by how options are handled in:

• install:api
• install:broadcasting
• migrate

From a user's perspective, I do think having a confirmation presented in certain circumstances is a nice QoL improvement instead of them being required to re-run commands with different arguments and options. To your point, that is something that should be consistent with other file generation commands:

• lang:publish
• config:publish
• stub:publish
• vendor:publish

If a PR would be welcomed to additionally make those changes for consistency, I could do so.