fix(transfer): handle decline and cancel across wallets

[hariclerry]

Description

Fix transfer decline and cancellation failures when a transfer belongs to a second wallet owned by the same account.

Issue(s) addressed

• Resolves Decline crashes with 500 when the transfer was sent to a second wallet #599

What kind of change(s) does this PR introduce?

• Enhancement
• Bug fix
• Refactor

Please check if the PR fulfils these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Issue

What is the current behavior?

• Declining or cancelling a transfer can return HTTP 500 when the transfer is associated with a second wallet. The service looks up the transfer using the login wallet, receives no result, and then attempts to read originating_wallet from undefined.

What is the new behavior?

• Decline and cancel now use the existing transfer lookup helper. This preserves
  the account wallet visibility and authorization checks and returns a controlled 404 when the transfer is not found or is not related to the requesting account.

• Added regression tests covering missing transfers for both decline and cancel,
  including transaction rollback and prevention of mutation or event logging.

Breaking change

Does this PR introduce a breaking change?

• No breaking change.

Other useful information

• Needs confirmation on whether the PR should target keycloak or `master

[dadiorchen]

@samwel141 can you help review this?

[samwel141]

@hariclerry you'll need to rebase onto keycloak and switch the base, it's still targeting master.

[samwel141]

But also its not a blocker it can be merged after release @dadiorchen, @mahdi2ba also mentioned in the issue #599