SSRS rptproj rdl files and assets are not copied to output directory when using /t:clean;build.

### Steps to reproduce
Ran into this issue using Azure Devops and narrowed it down to MSBuild. If I use the targets of `clean` and `build` the files and assets (images and what not) are not copied to the `OutputPath` but if I use `/t:build` it does copy the files. This reproduced with multiple different rptproj files including a brand new project created in Visual Studio 2019 (xml below).

Project file
```xml

Debug
bin\Debug
2
False
False
SSRS2016
Win32
NewReports
Datasets
Data Sources
Report Parts
http://localhost/reportserver


DebugLocal
bin\DebugLocal
2
False
False
SSRS2016
Win32
NewReports
Datasets
Data Sources
Report Parts
http://localhost/reportserver


Release
bin\Release
2
False
False
SSRS2016
Win32
NewReports
Datasets
Data Sources
Report Parts
http://localhost/reportserver


$base64$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
@(DataSource)
@(DataSet)
@(Report)

```

MSBuild location: `C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Current\Bin> `
(Some paths removed to protect sensitive information)
Working MSBuild command executed:
```
.\msbuild.exe "\NewReports.rptproj" /t:"Build" /p:platform="any cpu" /p:configuration="Release" /p:VisualStudioVersion="16.0"
```
Output:
```
Microsoft (R) Build Engine version 16.0.461+g6ff56ef63c for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

Build started 5/10/2019 12:39:19 PM.
Project "\NewReports.rptproj" on node 1 (Build target(s)).
ReportBuilderTarget:
Building the report, Certificate.rdl, for SQL Server 2016 Reporting Services.
Building the shared data source 'DataSource1.rds'.
Done Building Project "\NewReports.rptproj" (Build target(s)).

Build succeeded.
0 Warning(s)
0 Error(s)

Time Elapsed 00:00:00.19
```
Not Working:
Working MSBuild command executed:
```
.\msbuild.exe "\NewReports.rptproj" /t:"Clean;Build" /p:platform="any cpu" /p:configuration="Release" /p:VisualStudioVersion="16.0"
```
Output:
```
Microsoft (R) Build Engine version 16.0.461+g6ff56ef63c for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

Build started 5/10/2019 12:37:16 PM.

Build succeeded.
0 Warning(s)
0 Error(s)

Time Elapsed 00:00:00.14
```
### Expected behavior
RDLs built for designated version of SQL Reporting Server should be in the designated `OutputPath` for the configuration built.

### Actual behavior
No files are output to the `OutputPath`

### Environment data
`msbuild /version` output:
Locally: Microsoft (R) Build Engine version 16.0.461+g6ff56ef63c for .NET Framework
Also reproduces on Azure Devops Pipelines
OS info:
Windows 10, Visual Studio 2019,
Azure Hosted 2017, Latest Visual Studio

Edited to add, in Azure Devops Pipeline I had to uncheck "clean" in the Visual Studio Build task to get it to work there.