`az upgrade` fails on Azure DevOps Linux agents

**Describe the bug**
`az cli` on the default build server is outdated and cannot be upgraded. The version in the build agent has a know bug that blocks deployments

**To Reproduce**
Run a pipeline on the default Azure DevOps build server
```
- task: AzureCLI@2
displayName: Try to upgrade az cli
inputs:
failOnStandardError: true
azureSubscription: $(Subscription)
scriptType: bash
scriptLocation: inlineScript
inlineScript: |
az upgrade --yes
```

**Expected behavior**
the az upgrade succeeds

**Environment summary**
```
### Build agent
2021-06-04T22:08:16.2093723Z ##[section]Starting: Initialize job
2021-06-04T22:08:16.2095017Z Agent name: 'Azure Pipelines 6'
2021-06-04T22:08:16.2095440Z Agent machine name: 'fv-az70-667'
2021-06-04T22:08:16.2095707Z Current agent version: '2.187.2'
2021-06-04T22:08:16.2135395Z ##[group]Operating System
2021-06-04T22:08:16.2135657Z Ubuntu
2021-06-04T22:08:16.2135832Z 16.04.7
2021-06-04T22:08:16.2135983Z LTS
2021-06-04T22:08:16.2136161Z ##[endgroup]
2021-06-04T22:08:16.2136350Z ##[group]Virtual Environment
2021-06-04T22:08:16.2136590Z Environment: ubuntu-16.04
2021-06-04T22:08:16.2136809Z Version: 20210531.0
2021-06-04T22:08:16.2137135Z Included Software: https://github.com/actions/virtual-environments/blob/ubuntu16/20210531.0/images/linux/Ubuntu1604-README.md
2021-06-04T22:08:16.2137571Z Image Release: https://github.com/actions/virtual-environments/releases/tag/ubuntu16%2F20210531.0
2021-06-04T22:08:16.2138126Z ##[endgroup]
2021-06-04T22:08:16.2139345Z Current image version: '20210531.0'
2021-06-04T22:08:16.2153862Z Agent running as: 'vsts'
2021-06-04T22:08:16.2203634Z Prepare build directory.
2021-06-04T22:08:16.2501236Z Set build variables.
2021-06-04T22:08:16.2535532Z Download all required tasks.
2021-06-04T22:08:16.2654805Z Downloading task: AzureCLI (2.1.0)
2021-06-04T22:08:17.0162300Z Checking job knob settings.
2021-06-04T22:08:17.0171242Z Knob: AgentToolsDirectory = /opt/hostedtoolcache Source: ${AGENT_TOOLSDIRECTORY}
2021-06-04T22:08:17.0172612Z Knob: AgentPerflog = /home/vsts/perflog Source: ${VSTS_AGENT_PERFLOG}
2021-06-04T22:08:17.0175023Z Knob: TaskRestrictionsEnforcementMode = Enabled Source: $(agent.taskRestrictionsEnforcementMode)
2021-06-04T22:08:17.0175872Z Knob: EnableTaskRestrictionsTelemetry = true Source: $(agent.enableTaskRestrictionsTelemetry)
2021-06-04T22:08:17.0176688Z Finished checking job knob settings.
2021-06-04T22:08:17.0805808Z Plugin: 'Test Result Parser plugin' is running in background.
2021-06-04T22:08:17.0806186Z Plugin: 'Test File Publisher plugin' is running in background.
2021-06-04T22:08:17.0806977Z Start tracking orphan processes.
2021-06-04T22:08:17.1033468Z ##[section]Finishing: Initialize job
```

### Upgrade Results
```
2021-06-04T21:44:41.5163343Z ##[section]Starting: test12 Sandbox Deploy Service Settings
2021-06-04T21:44:41.5173097Z ==============================================================================
2021-06-04T21:44:41.5173724Z Task : Azure CLI
2021-06-04T21:44:41.5174360Z Description : Run Azure CLI commands against an Azure subscription in a PowerShell Core/Shell script when running on Linux agent or PowerShell/PowerShell Core/Batch script when running on Windows agent.
2021-06-04T21:44:41.5175014Z Version : 2.1.0
2021-06-04T21:44:41.5175383Z Author : Microsoft Corporation
2021-06-04T21:44:41.5175865Z Help : https://docs.microsoft.com/azure/devops/pipelines/tasks/deploy/azure-cli
2021-06-04T21:44:41.5176382Z ==============================================================================
2021-06-04T21:44:41.6616357Z [command]/usr/bin/az --version
2021-06-04T21:44:42.7029599Z azure-cli 2.24.0 *
2021-06-04T21:44:42.7030438Z
2021-06-04T21:44:42.7031018Z core 2.24.0 *
2021-06-04T21:44:42.7031768Z telemetry 1.0.6
2021-06-04T21:44:42.7032131Z
2021-06-04T21:44:42.7032575Z Extensions:
2021-06-04T21:44:42.7033375Z azure-devops 0.18.0
2021-06-04T21:44:42.7033780Z
2021-06-04T21:44:42.7034511Z Python location '/opt/az/bin/python3'
2021-06-04T21:44:42.7035391Z Extensions directory '/opt/az/azcliextensions'
2021-06-04T21:44:42.7035813Z
2021-06-04T21:44:42.7036367Z Python (Linux) 3.6.10 (default, May 21 2021, 07:22:47)
2021-06-04T21:44:42.7036954Z [GCC 5.4.0 20160609]
2021-06-04T21:44:42.7037278Z
2021-06-04T21:44:42.7037772Z Legal docs and information: aka.ms/AzureCliLegal
2021-06-04T21:44:42.7038128Z
2021-06-04T21:44:42.7038403Z
2021-06-04T21:44:42.7047675Z WARNING: You have 2 updates available. Consider updating your CLI installation with 'az upgrade'
2021-06-04T21:44:42.7048776Z
2021-06-04T21:44:42.7049555Z Please let us know how we are doing: https://aka.ms/azureclihats
2021-06-04T21:44:42.7051521Z and let us know if you're interested in trying out our newest features: https://aka.ms/CLIUXstudy
2021-06-04T21:44:42.7056539Z Setting AZURE_CONFIG_DIR env variable to: /home/vsts/work/_temp/.azclitask

2021-06-04T21:44:46.0158633Z WARNING: This command is in preview and under development. Reference and support levels: https://aka.ms/CLI_refstatus
2021-06-04T21:44:46.0160306Z WARNING: Your current Azure CLI version is 2.24.0. It will be updated to 2.24.2.
2021-06-04T21:44:46.1098692Z Hit:1 http://azure.archive.ubuntu.com/ubuntu xenial InRelease
2021-06-04T21:44:46.1100718Z Get:2 http://azure.archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
2021-06-04T21:44:46.1133758Z Get:3 http://azure.archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB]
2021-06-04T21:44:46.1361403Z Get:4 http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
2021-06-04T21:44:46.1772743Z Get:5 https://packages.microsoft.com/ubuntu/16.04/prod xenial InRelease [4,002 B]
2021-06-04T21:44:46.2575656Z Hit:6 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial InRelease
2021-06-04T21:44:46.2974062Z Get:7 http://azure.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [2,049 kB]
2021-06-04T21:44:46.3987911Z Get:8 https://esm.ubuntu.com/infra/ubuntu xenial-infra-security InRelease [7,500 B]
2021-06-04T21:44:46.4154694Z Hit:9 http://ppa.launchpad.net/mercurial-ppa/releases/ubuntu xenial InRelease
2021-06-04T21:44:46.4184163Z Get:10 https://esm.ubuntu.com/infra/ubuntu xenial-infra-updates InRelease [7,475 B]
2021-06-04T21:44:46.4489278Z Get:11 https://packages.microsoft.com/ubuntu/16.04/prod xenial/main amd64 Packages [210 kB]
2021-06-04T21:44:46.5750744Z Get:12 http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease [23.9 kB]
2021-06-04T21:44:46.6546375Z Get:13 https://esm.ubuntu.com/infra/ubuntu xenial-infra-security/main amd64 Packages [76.9 kB]
2021-06-04T21:44:46.8291283Z Get:14 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease [23.8 kB]
2021-06-04T21:44:47.0823779Z Get:15 http://ppa.launchpad.net/ondrej/php/ubuntu xenial/main amd64 Packages [1,260 B]
2021-06-04T21:44:47.2438757Z Get:16 http://ppa.launchpad.net/ondrej/php/ubuntu xenial/main Translation-en [1,256 B]
2021-06-04T21:44:47.4067698Z Get:17 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial/main amd64 Packages [88.6 kB]
2021-06-04T21:44:47.8003261Z Get:18 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial/main Translation-en [26.8 kB]
2021-06-04T21:44:50.2643696Z Fetched 2,845 kB in 1s (1,560 kB/s)
2021-06-04T21:44:51.1960297Z Reading package lists...
2021-06-04T21:44:51.2588165Z Reading package lists...
2021-06-04T21:44:51.4019338Z Building dependency tree...
2021-06-04T21:44:51.4027718Z Reading state information...
2021-06-04T21:44:51.5208335Z azure-cli is already the newest version (2.24.0-1~xenial).
2021-06-04T21:44:51.5542588Z 0 upgraded, 0 newly installed, 0 to remove and 28 not upgraded.

2021-06-04T21:44:51.8136416Z WARNING: CLI upgrade failed or aborted.

2021-06-04T21:45:05.7182633Z ##[error]WARNING: This command is in preview and under development. Reference and support levels: https://aka.ms/CLI_refstatus
2021-06-04T21:45:05.7193020Z ##[error]WARNING: Your current Azure CLI version is 2.24.0. It will be updated to 2.24.2.
2021-06-04T21:45:05.7194582Z ##[error]WARNING: CLI upgrade failed or aborted.
2021-06-04T21:45:05.7196430Z ##[error]Script has output to stderr. Failing as failOnStdErr is set to true.
2021-06-04T21:45:05.7202522Z [command]/usr/bin/az account clear
2021-06-04T21:45:05.9729123Z ##[section]Finishing: test12 Sandbox Deploy Service Settings
```