func templates list returns "Value cannot be null"

This is what's happening:
```
forla@DESKTOP-PGDBNMB MINGW64 /d/workspace/flamingo-rtc/serverless (forlayo_167_timeline)
$ npm i -g azure-functions-core-tools
C:\Program Files\nodejs\azfun -> C:\Program Files\nodejs\node_modules\azure-functions-core-tools\lib\main.js
C:\Program Files\nodejs\azurefunctions -> C:\Program Files\nodejs\node_modules\azure-functions-core-tools\lib\main.js
C:\Program Files\nodejs\func -> C:\Program Files\nodejs\node_modules\azure-functions-core-tools\lib\main.js

> azure-functions-core-tools@2.7.2628 postinstall C:\Program Files\nodejs\node_modules\azure-functions-core-tools
> node lib/install.js

attempting to GET "https://functionscdn.azureedge.net/public/2.7.2628/Azure.Functions.Cli.win-x64.2.7.2628.zip"
[==================] Downloading Azure Functions Core Tools

Telemetry
---------
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The data is anonymous and doesn't include any user specific or personal information. The data is collected by Microsoft.

You can opt-out of telemetry by setting the FUNCTIONS_CORE_TOOLS_TELEMETRY_OPTOUT environment variable to '1' or 'true' using your favorite shell.

+ azure-functions-core-tools@2.7.2628
updated 1 package in 18.362s

forla@DESKTOP-PGDBNMB MINGW64 /d/workspace/flamingo-rtc/serverless (forlayo_167_timeline)
$ func templates list
Value cannot be null.
Parameter name: value

forla@DESKTOP-PGDBNMB MINGW64 /d/workspace/flamingo-rtc/serverless (forlayo_167_timeline)
$ export CLI_DEBUG=1

forla@DESKTOP-PGDBNMB MINGW64 /d/workspace/flamingo-rtc/serverless (forlayo_167_timeline)
$ func templates list
System.ArgumentNullException: Value cannot be null.
Parameter name: value
at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)
at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)
at Azure.Functions.Cli.Common.TemplatesManager.GetTemplates() in D:\a\1\s\src\Azure.Functions.Cli\Common\TemplatesManager.cs:line 42
at Azure.Functions.Cli.Actions.LocalActions.ListTemplatesAction.RunAsync() in D:\a\1\s\src\Azure.Functions.Cli\Actions\LocalActions\ListTemplatesAction.cs:line 36
at Azure.Functions.Cli.ConsoleApp.RunAsync[T](String[] args, IContainer container) in D:\a\1\s\src\Azure.Functions.Cli\ConsoleApp.cs:line 66
```

As you can see the functions cli is recently installed and I am just trying to list the templates, but got an error all times. I had also enabled the CLI_DEBUG and apparently is something deserializing a json :S

Trying to create a function, I got same issue
```
forla@DESKTOP-PGDBNMB MINGW64 /d/workspace/flamingo-rtc/serverless (forlayo_167_timeline)
$ func new -l JavaScript -n Notes -t 'HTTP trigger'
System.ArgumentNullException: Value cannot be null.
Parameter name: value
at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)
at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)
at Azure.Functions.Cli.Common.TemplatesManager.GetTemplates() in D:\a\1\s\src\Azure.Functions.Cli\Common\TemplatesManager.cs:line 42
at Azure.Functions.Cli.Actions.LocalActions.CreateFunctionAction.RunAsync() in D:\a\1\s\src\Azure.Functions.Cli\Actions\LocalActions\CreateFunctionAction.cs:line 78
at Azure.Functions.Cli.ConsoleApp.RunAsync[T](String[] args, IContainer container) in D:\a\1\s\src\Azure.Functions.Cli\ConsoleApp.cs:line 66
```

Start with Common/TemplatesManager.cs at line 42 and trace the template-loading path used by ListTemplatesAction.cs line 36 and CreateFunctionAction.cs line 78. Reproduce the failure with `func templates list` and `func new`, then verify both commands complete without the null-value exception.

Written by the indexing model from the issue text.