Improve error messaging in lasso functions

[timcadman]

Describe the bug
Often lasso functions (e.g. ds.LassoCov_CVInSite) fail with error messages which are quite hard to understand. For example:

$eden_nan [1] "Execution failed: 400 Bad Request: \"{\"status\":\"400\",\"key\":\"REvaluationRuntimeException\",\"args\":[],\"message\":\"Error in t(x) %*% x[, covar, drop = FALSE] : \\n requires numeric/complex matrix/vector arguments\\n\"}\""

$inma_gip [1] "Command 'glmDS1(Y_lm ~ fdens_trans_iqr_c + frich_trans_iqr_c + hdres_trans_iqr_c + \n indtr_trans_iqr_c + ldres_trans_iqr_c - 1, \"gaussian\", NULL, \n NULL, \"data_lm\")' failed on 'inma_gip': Error while evaluating 'dsBase::glmDS1(Y_lm~fdens_trans_iqr_c+frich_trans_iqr_c+hdres_trans_iqr_c+indtr_trans_iqr_c+ldres_trans_iqr_c-1, \"gaussian\", NULL, NULL, \"data_lm\")' -> Error in glm.fit(x = structure(numeric(0), dim = c(0L, 5L), dimnames = list( : \n object 'fit' not found\n"

Expected behavior
Error messages are returned providing more detail as to why the functions have failed. Perhaps what is required is additional checks before running the data, e.g. for missingness, data types, or other features of the data could cause Lasso to fail?