Remove outstanding principal

[toninorair]

Outstanding principal calculations won't be valid if HubPortal is not earning

[github-actions]

LCOV of commit 8a54027 during Forge Coverage #128

Summary coverage rate:
  lines......: 84.2% (176 of 209 lines)
  functions..: 74.3% (52 of 70 functions)
  branches...: 75.0% (36 of 48 branches)

Files changed coverage rate:
                                 |Lines       |Functions  |Branches    
  Filename                       |Rate     Num|Rate    Num|Rate     Num
  =====================================================================
  src/HubPortal.sol              | 100%     33| 100%     9| 100%      4
  src/Portal.sol                 | 100%     25|81.8%    11| 100%      5
  src/SpokePortal.sol            | 100%     34| 100%     7| 100%     11

[github-actions]

Changes to gas cost

Generated at commit: 94f7567ba7f8ff510988e11ed31974aa2a0589bf, compared to commit: aa86b2676d1e606844ecf24c70e7db8b902ac5f7

🧾 Summary (20% most significant diffs)

Contract	Method	Avg (+/-)	%
SpokePortal	attestationReceived transfer	-31,223 ✅ -168,583 ✅	-27.16% -55.20%

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Full diff report 👇

Contract	Deployment Cost (+/-)	Method	Min (+/-)	%	Avg (+/-)	%	Median (+/-)	%	Max (+/-)	%	# Calls (+/-)
SpokePortal	5,217,265 (-175,084)	attestationReceived currentIndex mToken registrar setPeer setTransceiver transfer	54,004 (-5,802) 1,150 (-50) 323 (+22) 371 (+110) 54,172 (-67) 188,471 (-45) 136,834 (-162,383)	-9.70% -4.17% +7.31% +42.15% -0.12% -0.02% -54.27%	83,744 (-31,223) 1,150 (-50) 323 (+22) 371 (+110) 54,172 (-67) 188,471 (-45) 136,834 (-168,583)	-27.16% -4.17% +7.31% +42.15% -0.12% -0.02% -55.20%	78,972 (-60,912) 1,150 (-50) 323 (+22) 371 (+110) 54,172 (-67) 188,471 (-45) 136,834 (-171,683)	-43.54% -4.17% +7.31% +42.15% -0.12% -0.02% -55.65%	114,865 (-25,019) 1,150 (-50) 323 (+22) 371 (+110) 54,172 (-67) 188,471 (-45) 136,834 (-171,683)	-17.89% -4.17% +7.31% +42.15% -0.12% -0.02% -55.65%	17 (+9) 1 (-1) 1 (-30) 1 (-30) 16 (-28) 16 (-15) 1 (-2)