### Description

A query like `from employees | where true` is perfectly valid. So is `from employees | where still_hired`. In other words, a simple boolean expression is accepted, even if that expression is a field. For fields `where [field_name]` is the short version of `where [field_name] == true`.

But, for fields that are not booleans `from employees | where salary` for example, ESQL throws an exception:

```
                "type": "class_cast_exception",
                "reason": "class org.elasticsearch.compute.data.IntVectorBlock cannot be cast to class org.elasticsearch.compute.data.BooleanBlock (org.elasticsearch.compute.data.IntVectorBlock and org.elasticsearch.compute.data.BooleanBlock are in unnamed module of loader java.net.FactoryURLClassLoader @c6a692e)"
```

The error message should be more user-friendly, like validating the parameters of regular functions.
x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/analysis/Verifier.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */
package org.elasticsearch.xpack.esql.analysis;
import org.elasticsearch.xpack.esql.evaluator.predicate.operator.comparison.Equals;
import org.elasticsearch.xpack.esql.evaluator.predicate.operator.comparison.NotEquals;
import org.elasticsearch.xpack.esql.expression.function.UnsupportedAttribute;
import org.elasticsearch.xpack.esql.expression.predicate.operator.arithmetic.Neg;
import org.elasticsearch.xpack.esql.plan.logical.Dissect;
import org.elasticsearch.xpack.esql.plan.logical.Eval;
import org.elasticsearch.xpack.esql.plan.logical.Grok;
import org.elasticsearch.xpack.esql.plan.logical.RegexExtract;
import org.elasticsearch.xpack.esql.plan.logical.Row;
import org.elasticsearch.xpack.esql.stats.FeatureMetric;
import org.elasticsearch.xpack.esql.stats.Metrics;
import org.elasticsearch.xpack.esql.type.EsqlDataTypes;
import org.elasticsearch.xpack.ql.capabilities.Unresolvable;
import org.elasticsearch.xpack.ql.common.Failure;
import org.elasticsearch.xpack.ql.expression.Alias;
import org.elasticsearch.xpack.ql.expression.Expression;
import org.elasticsearch.xpack.ql.expression.FieldAttribute;
import org.elasticsearch.xpack.ql.expression.Literal;
import org.elasticsearch.xpack.ql.expression.MetadataAttribute;