Add strong typing for Google Sheet API conditionnal formatting - Type of BooleanRules

Please add strongly type for the condition's types in boolean rules for conditionnal formatting.
Today, it is `string or undefined`:

below the enum I have created, that may helps

```
enum EGoogleSheetBooleanConditionsTypes {
CONDITION_TYPE_UNSPECIFIED = "CONDITION_TYPE_UNSPECIFIED",
NUMBER_GREATER = "NUMBER_GREATER",
NUMBER_GREATER_THAN_EQ = "NUMBER_GREATER_THAN_EQ",
NUMBER_LESS = "NUMBER_LESS",
NUMBER_LESS_THAN_EQ = "NUMBER_LESS_THAN_EQ",
NUMBER_EQ = "NUMBER_EQ",
NUMBER_NOT_EQ = "NUMBER_NOT_EQ",
NUMBER_BETWEEN = "NUMBER_BETWEEN",
NUMBER_NOT_BETWEEN = "NUMBER_NOT_BETWEEN",
TEXT_CONTAINS = "TEXT_CONTAINS",
TEXT_NOT_CONTAINS = "TEXT_NOT_CONTAINS",
TEXT_STARTS_WITH = "TEXT_STARTS_WITH",
TEXT_ENDS_WITH = "TEXT_ENDS_WITH",
TEXT_EQ = "TEXT_EQ",
TEXT_IS_EMAIL = "TEXT_IS_EMAIL",
TEXT_IS_URL = "TEXT_IS_URL",
DATE_EQ = "DATE_EQ",
DATE_BEFORE = "DATE_BEFORE",
DATE_AFTER = "DATE_AFTER",
DATE_ON_OR_BEFORE = "DATE_ON_OR_BEFORE",
DATE_ON_OR_AFTER = "DATE_ON_OR_AFTER",
DATE_BETWEEN = "DATE_BETWEEN",
DATE_NOT_BETWEEN = "DATE_NOT_BETWEEN",
DATE_IS_VALID = "DATE_IS_VALID",
ONE_OF_RANGE = "ONE_OF_RANGE",
ONE_OF_LIST = "ONE_OF_LIST",
BLANK = "BLANK",
NOT_BLANK = "NOT_BLANK",
CUSTOM_FORMULA = "CUSTOM_FORMULA",
BOOLEAN = "BOOLEAN",
TEXT_NOT_EQ = "TEXT_NOT_EQ",
DATE_NOT_EQ = "DATE_NOT_EQ",
}
```

example to color in red negative cells

```
const conditionnalFormatting: sheets_v4.Schema$Request = {
addConditionalFormatRule: {
rule: {
ranges: [
{
sheetId,
startColumnIndex: 1,
endColumnIndex: 10,
},
],
booleanRule: {
condition: {
type: EGoogleSheetBooleanConditionsTypes.NUMBER_LESS,
values: [
{
userEnteredValue: "0",
},
],
},
format: {
textFormat: {
foregroundColor: {
red: 1,
},
},
},
},
},
index: 0,
},
};

```