Support whitespaces in the middle of "ELSE IF" condition key word

[Danieladu]

fix: #2235

Support this format:

# template
- if: {expression1}
  - say hi
- else IF: {expression2} // Originally did not support spaces in the middle
  - say hello
- ELSE:
  - bye

[coveralls]

Pull Request Test Coverage Report for Build 83383

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 78.636%

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Totals
Change from base Build 83280:	0.0%
Covered Lines:	5418
Relevant Lines:	6890

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💛 - Coveralls

[fuselabs]

✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.dll compared against version 4.5.3
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✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.TemplateManager.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Configuration.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Connector.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Schema.dll compared against version 4.5.3

[fuselabs]

✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.AI.Luis.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.AI.QnA.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.ApplicationInsights.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.Azure.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.Dialogs.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Builder.TemplateManager.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Configuration.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Connector.dll compared against version 4.5.3
✔️ No Binary Compatibility issues for Microsoft.Bot.Schema.dll compared against version 4.5.3