[CBW-987] Fixed error message shown to the user on backend error in delegation Update

[czerwix]

Purpose

Fixed error message is shown to the user on backend error in delegation Update. Updated balance calculation logic in DelegationActivity to account for delegated/shielded amounts

Checklist

• [x] My code follows the style of this project.
• [x] The code compiles without warnings.
• [x] I have performed a self-review of the changes.
• [x] I have documented my code, in particular the intent of the hard-to-understand areas.
• [x] (If necessary) I have updated the CHANGELOG.

CLA acceptance

_Remove if not applicable.

By submitting the contribution I accept the terms and conditions of the Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• [x] I accept the above linked CLA.

[github-actions[bot]]

File	Coverage [0%]	:x:
BackendErrorHandler.kt	0%	:x:

Total Project Coverage	0.83%	:x:

[bisgardo]

Please update the PR title/description to also cover the changes in DelegationRegisterAmountActivity.kt. Right now they only reflect the error message change.

[github-actions[bot]]

File	Coverage [0%]	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:

Total Project Coverage	0.83%	:x:

[github-actions[bot]]

File	Coverage [0%]	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:

Total Project Coverage	0.83%	:x:

[github-actions[bot]]

File	Coverage [0%]	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:

Total Project Coverage	0.83%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x:

[github-actions[bot]]

File	Coverage [1.37%]	:x:
StakeAmountInputValidator.kt	19.42%	:x:
DelegationRegisterAmountActivity.kt	0%	:x:
DelegationBakerViewModel.kt	0%	:x:
BackendErrorHandler.kt	0%	:x:
BakerRegisterAmountActivity.kt	0%	:x:
Account.kt	0%	:x:

Total Project Coverage	0.91%	:x: