fix(docs): Remove unnecessary security warning for MacOS

The security warning applies for downloaded executables. If you are
following the instructions the toolchain is installed with brew and
the security warning does not apply. This is explained in the removed
link.

docs/docs/development/setup.md

@@ -335,20 +335,12 @@ Since the Zephyr™ SDK is not available for Windows, we recommending following
 
 #### GNU ARM Embedded
 
-Since the Zephyr™ SDK is not available for macOS, we recommending following the steps to install the [GNU ARM Embedded](https://docs.zephyrproject.org/2.5.0/getting_started/toolchain_3rd_party_x_compilers.html#gnu-arm-embedded).
-
-The install command is:
+Since the Zephyr™ SDK is not available for macOS, we recommending following the steps to install the GNU ARM Embedded toolchain:
 
 ```
 brew install --cask gcc-arm-embedded
 ```
 
-:::warning Security Controls Workaround
-
-Please be sure to read the [additional setup instructions](https://docs.zephyrproject.org/2.5.0/getting_started/installation_mac.html#mac-gatekeeper) needed to address security controls found in macOS 10.15 Catalina and newer
-
-:::
-
 </TabItem>
 </OsTabs>