fix(bridge-ui): manual import not resetting correctly

[TheMindkiller]

Observed behavior:

When you manually add a NFT and go back to the start, the contract address input remains

This blocks the UI, making interactions impossible without refresh!

Console output:

Uncaught (in promise) TypeError: Cannot set properties of undefined (setting 'value')
    at clearAddress (AddressInput.svelte:52:18)
    at AddressInput.svelte:73:5
    at run (chunk-4BDLA4GE.js?v=b5783581:30:10)
    at Array.forEach (<anonymous>)
    at run_all (chunk-4BDLA4GE.js?v=b5783581:36:7)
    at destroy_component (chunk-4BDLA4GE.js?v=b5783581:2150:5)
    at Object.destroy [as d] (ManualImport.svelte:192:39)
    at destroy_component (chunk-4BDLA4GE.js?v=b5783581:2151:32)
    at Object.destroy [as d] (ImportStep.svelte:16:40)
    at chunk-4BDLA4GE.js?v=b5783581:1408:17

Solution:
onDestroy() calls clearAddress(), but when it is not loaded it cannot reset the inputElement. So you should check if it exists.
Simple fix!

Go Taiko!! 🥁