Implements `randomWalletFromFaucet` for Improved `XRPClient` Integration Tests

[amiecorso]

High Level Overview of Change

This PR implements the test utility randomWalletFromFaucet, which generates a random wallet and then requests funds via the XRPL Testnet faucet (https://xrpl.org/xrp-testnet-faucet.html). Integration tests are refactored to use a new funded address each time, which should eliminate the failures that occur due to sequence number clashes when different clients (via different CI runs) send transactions on behalf of the same account.

Context of Change

Type of Change

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [x] Refactor (non-breaking change that only restructures code)

Before / After

New addresses are used for integration tests where relevant.

Test Plan

Refactor integration tests where necessary. CI still passes.

[codecov[bot]]

Codecov Report

Merging #267 into master will increase coverage by 0.44%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #267      +/-   ##
==========================================
+ Coverage   90.01%   90.45%   +0.44%     
==========================================
  Files          42       43       +1     
  Lines         951      985      +34     
==========================================
+ Hits          856      891      +35     
+ Misses         95       94       -1     

Impacted Files	Coverage Δ
XpringKit/XRP/DefaultXRPClient.swift	98.14% <100.00%> (+0.13%)	:arrow_up:
XpringKit/XRP/Model/AccountRootFlag.swift	100.00% <100.00%> (ø)
XpringKit/XRP/Model/PaymentFlag.swift	100.00% <100.00%> (ø)
...l/XRPTransaction+Org_Xrpl_Rpc_V1_Transaction.swift	96.00% <100.00%> (ø)
XpringKit/XRP/RawTransactionStatus.swift	100.00% <100.00%> (ø)
XpringKit/XRP/ReliableSubmissionXRPClient.swift	95.77% <100.00%> (+1.33%)	:arrow_up:
XpringKit/XRP/XRPClient.swift	100.00% <100.00%> (ø)
XpringKit/XRP/WalletGenerationResult.swift	80.00% <0.00%> (+20.00%)	:arrow_up:

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