feat: Disable noUncheckedIndexedAccess since it forces ! anyway

[dvmoritzschoefl]

The problem:

TS cannot (yet) decide if static indexed access is valid or not. Example:

// columns is typed as T[] (without undefined/null)
if (columns.length === 3) {
    columns[0]... -> TS error
}

Also for loops are not inferable

for (let i = 0; i < 3; i++) {
    if (columns[i]) {
        columns[i]... -> TS error
    }
}

[puehringer]

I looked at this and it does effect non arrays as well, i.e. simple objects: https://www.typescriptlang.org/tsconfig/#noUncheckedIndexedAccess

I don't want to disable it for object access, as I think it is crucial there. Any alternative @dvmoritzschoefl?