fix(core): handle concurrent deletion and update of environment

[Divyanshu1998]

Linked issue

Resolves: Status: Open.
#2984

What kind of change does this PR introduce?

• Bug fix
• New feature
• Refactor
• Docs update
• CI update

What is the current behavior?

Application currently allows a deletion by SUPERADMIN (or a user with permission to edit/delete environments) to be overwritten if another user still has the edit form open and clicks save after the delete.

What is the new behavior?

• When the second user clicks save, a popup appears saying the environment is already deleted.
• The user is then redirected to the environments list page.

Other information

• Added a check before saving an edit to verify the environment still exists.
• Added regression test in EnvsClustersTenantsControllerServiceTest to cover this scenario.

Requirements (all must be checked before review)

• The pull request title follows our guidelines
• Tests for the changes have been added (regression test included)
• The latest changes from the main branch have been pulled
• pnpm lint has been run successfully

[muralibasani]

@Divyanshu1998 can you pls check the failing pipeline ?

[Divyanshu1998]

I'll check and fix