Fix: Add parentheses around labels merge operation

[ShivaniBanke]

Current State

The label merging logic has an incorrect operator precedence, which could lead to unexpected behavior when combining team and alert rule-specific labels. The addition operator (+) for merging label objects was being evaluated before the conditional expressions.

Changes

• Added explicit parentheses around the first operand in the labels merge operation
• Ensured proper evaluation order when combining team and rule-specific labels

Notes

• This is a non-breaking change that improves the reliability of label merging
• The fix ensures consistent behavior across different label configurations