addDaysQuery produces erroneous query for Redshift driver

[krystian8207]

Describe the bug
The number argument passed to addDaysQuery and minusDaysQuery is treated by dbplyr parser as double/numeric.
As a result for Redshift driver we get DATEADD(DAY, <double>, "variable") statement.
Such statement produces error as DATEADD is not supporting doubles as a second argument for Redshift.

To Reproduce

# unfortunately the needs an active Redshift connection in order to reproduce
db <- DBI::dbConnect(
  RPostgres::Redshift(),
  dbname   = Sys.getenv("REDSHIFT_DBNAME"),
  host     = Sys.getenv("REDSHIFT_HOST"),
  port     = Sys.getenv("REDSHIFT_PORT"),
  user     = Sys.getenv("REDSHIFT_USERNAME"),
  password = Sys.getenv("REDSHIFT_PASSWORD")
)
cdm <- CDMConnector::cdmFromCon(
  con = db,
  cdmSchema = c(schema = Sys.getenv("CDM_SCHEMA")),
  writeSchema = c(schema = Sys.getenv("CDM_WRITE_SCHEMA"), prefix = "test"),
  cdmName = Sys.getenv("REDSHIFT_DBNAME")
)
query_expr <- IncidencePrevalence:::addDaysQuery(cdm, "index_date", 1, "day", "expr")
my_tbl <- dplyr::tbl(db, "mytbl")
inc_date_tbl <- my_tbl |> dplyr::mutate(inc_date = !!query_expr$expr) 
inc_date_tbl |> dplyr::show_query()
#> <SQL>
#> SELECT "mytbl".*, DATEADD(DAY, 1.0, "index_date") AS "inc_date"
#> FROM "mytbl"

inc_date_tbl |> dplyr::collect()
#> Error in `dplyr::collect()`:
#> ! Failed to collect lazy table.
#> Caused by error:
#> ! Failed to prepare query: ERROR:  function pg_catalog.date_add("unknown", numeric, date) does not exist
#> HINT:  No function matches the given name and argument types. You may need to add explicit type casts.

Desktop (please complete the following information):

> sessionInfo()
R version 4.2.1 (2022-06-23)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.5 LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3
LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.so.3

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8   
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices datasets  utils     methods   base     

other attached packages:
[1] dbplyr_2.5.0    dplyr_1.1.4     DBI_1.2.1       RPostgres_1.4.5 odbc_1.3.5     

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.12                 pillar_1.9.0                compiler_4.2.1              CDMConnector_1.4.0          tools_4.2.1                
 [6] PatientProfiles_1.1.0       bit_4.0.5                   jsonlite_1.8.8              lubridate_1.9.3             lifecycle_1.0.4            
[11] tibble_3.2.1                timechange_0.2.0            pkgconfig_2.0.3             rlang_1.1.3                 cli_3.6.2                  
[16] rstudioapi_0.16.0           clock_0.7.0                 withr_3.0.0                 generics_0.1.3              vctrs_0.6.5                
[21] hms_1.1.3                   rprojroot_2.0.3             bit64_4.0.5                 tidyselect_1.2.1            glue_1.7.0                 
[26] here_1.0.1                  IncidencePrevalence_0.7.3   R6_2.5.1                    fansi_1.0.6                 tzdb_0.4.0                 
[31] tidyr_1.3.1                 purrr_1.0.2                 blob_1.2.4                  magrittr_2.0.3              omopgenerics_0.2.1