fix(lambda): Update error messaging in AppBuilder

[seshubaws]

Problem

Several errors that were being shown to customers did not have enough information for them to take action on the problem.

Solution

Audited all errors and logs shown to customers and updated them to make them more legible and actionable.

---

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[github-actions]

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[Hweinstock]

Looks like some tests need updating once the relevant changes are finalized:

3 failing
  1) generateDeployedNode
       LambdaFunctionNode
         should log error message given any lambda client error:

      AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
+ actual - expected

+ '[Failed to retrieve deployed resource. Please ensure stack name, region, and account credentials are correct.]'
- '[Failed to retrive deployed resource.]'
      + expected - actual

      -[Failed to retrieve deployed resource. Please ensure stack name, region, and account credentials are correct.]
      +[Failed to retrive deployed resource.]
      
      at Context.<anonymous> (/Users/runner/work/aws-toolkit-vscode/aws-toolkit-vscode/packages/core/src/test/shared/applicationBuilder/explorer/nodes/deployedNode.test.ts:223:20)

  2) generateDeployedNode
       UnsupportedResourceNode
         should return a DeployedResourceNode with placeholder:

      AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
+ actual - expected

+ '[This resource is not yet supported in AppBuilder.]'
- '[This resource is not yet supported.]'
      + expected - actual

      -[This resource is not yet supported in AppBuilder.]
      +[This resource is not yet supported.]
      
      at Context.<anonymous> (/Users/runner/work/aws-toolkit-vscode/aws-toolkit-vscode/packages/core/src/test/shared/applicationBuilder/explorer/nodes/deployedNode.test.ts:377:20)

  3) AppNode
       getChildren
         should return placeholder item when encounter error:

      AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
+ actual - expected

+ '[Unable to load resource tree for this app. Ensure SAM template is correct.]'
- '[Unable to load Resource tree for this App. Update SAM template]'
      + expected - actual

      -[Unable to load resource tree for this app. Ensure SAM template is correct.]
      +[Unable to load Resource tree for this App. Update SAM template]