FINERACT-2730: add loan and savings transaction search

[AnvayKharb]

Description

This PR extends the global search functionality to support searching loan repayment and savings transactions.

Users can now search transactions using existing transaction identifiers without changing the current search endpoint or affecting existing search behavior.

Supported searches

Loan repayments

• Transaction ID
• External ID

Savings deposits and withdrawals

• Transaction ID
• External ID
• Reference Number (refNo)

Changes

• Added loanTransactions and savingsTransactions search resources.
• Extended the global search SQL to return matching loan repayment and savings transaction results.
• Added transaction metadata to the search response, including transaction ID, transaction type, account ID, account number, account type, external ID, and reference number where applicable.
• Preserved backward compatibility by adding nullable response fields without changing the existing API contract.
• Added integration tests covering transaction searches by transaction ID, external ID, and reference number.

Related Issue

FINERACT-2730

Screenshots

N/A

Checklist

• If you have multiple commits, they have been squashed into a single commit.
• Read and understood the contribution guidelines.
• Added or updated tests for the implemented functionality.
• Verified that existing search functionality continues to work.

[IOhacker]

LGTM