[TS] Fix TS errors in util directory

[Cal-L]

Description

Fix Typescript errors in the util directory

Technical Details

Number of errors by file

     1  app/util/address/index.test.ts:14
    23  app/util/conversion/index.test.ts:11
    22  app/util/custom-gas/index.test.ts:19
     1  app/util/date/index.test.ts:42
     3  app/util/general/index.test.ts:24
     4  app/util/networks/handleNetworkSwitch.ts:32
     2  app/util/networks/index.test.ts:108
    30  app/util/number/index.test.ts:108
     1  app/util/password/index.test.ts:6
     8  app/util/sync/index.test.ts:109
     1  app/util/tokens/tokens.test.ts:4
     7  app/util/transactions/index.test.ts

Acceptance Criteria

• running yarn tsc should not show any issues in the util directory