[VC-52458] Support both number and string for tsgID

[inteon]

Based on feedback, this change updates tsgID to accept both numbers and strings.
Previously, the Helm chart’s values.schema.json enforced tsgID as a string. However, this constraint introduced unnecessary friction for users during initial setup.
To improve the user experience, we now allow both numeric and string inputs. As a side effect, this adds some complexity to the chart implementation, requiring a workaround for a Helm issue related to scientific notation handling.

context: in #793 we enforced tsgID to be a string

$ helm template ./deploy/charts/discovery-agent \
    --set config.tsgID=111111111111111111111111 \
    --set config.clusterName=aaa | grep 1111
            - "111111111111111111111111"