Years have passed and we yet do not have an answer button on desktop teams, only mobile.
To resolve these problems, I created a Teams plugin that make this, is not the best solution, but is a solution.
I have not tried to publish on the store, I think Microsoft will not allow me, but if you think otherwise, message me.
You will need to sideload the Add-in on your company Teams.
You can use my free bot key
MICROSOFT_APP_ID=3fc983d9-b550-46b0-a54e-9aa25d9e1b48
All messages sent to the public service will not be persisted, analyzed or anything else, they will only be returned to the teams via the Azure Bot Service (only way I found to implement this, if you know another way, message me or submit a Pull Request).
I cannot guarantee that the service will be online all the time, if the usage surpasses my monthly budget, I will shutdown the bot for the month (I am only a single dev making 13k per year)
The Azure Bot Framework and Azure Functions is a Microsoft service, for privacy information about these services read they privacy policy.
THE BOT SERVICE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.