[vault] fix report.rs

[chopan123]

• warning: This addition operation could overflow.

  --> vault/src/report.rs:19:9
   |
19 |         self.locked_fee += total_fee;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s

• warning: This subtraction operation could underflow.

  --> vault/src/report.rs:27:9
   |
27 |         self.locked_fee -= amount;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s

• warning: This addition operation could overflow.

  --> vault/src/report.rs:28:9
   |
28 |         self.gains_or_losses += amount;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s

• warning: This subtraction operation could underflow.

  --> vault/src/report.rs:38:31
   |
38 |         let gains_or_losses = current_balance - prev_balance;
   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s

• warning: This addition operation could overflow.

  --> vault/src/report.rs:39:9
   |
39 |         self.gains_or_losses += gains_or_losses;
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s

• warning: Unsafe usage of unwrap

  --> vault/src/report.rs:61:25
   |
61 |         let numerator = report.locked_fee.checked_mul(defindex_fee as i128).unwrap();
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider pattern matching or using `if let` instead of `unwrap`

• warning: Unsafe usage of unwrap

  --> vault/src/report.rs:62:35
   |
62 |         let defindex_fee_amount = numerator.checked_div(MAX_BPS).unwrap();
   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider pattern matching or using `if let` instead of `unwrap`

• warning: This subtraction operation could underflow.

  --> vault/src/report.rs:64:32
   |
64 |         let vault_fee_amount = report.locked_fee - defindex_fee_amount;
   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Consider using the checked version of this operation/s